Method and apparatus for producing composite structure

ABSTRACT

The present invention relates to a method and apparatus for forming a composite structure, preferably for use in an absorbent structure used within the personal hygiene industry, such as for instance feminine hygiene garments, baby diapers and pants and adult incontinence garments. The present invention preferably provides a method and apparatus for depositing and positioning particulate materials in a desired pattern onto a moving carrier layer. The method allows accurate forming of a pattern of particulate material clusters at high production speed having improved attachment properties, with reduced raw material usage and relative low cost. The present invention foresees in the need for improved thin, flexible, lightweight absorbent structure having optimal absorption, distribution and retention.

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for depositingparticulate material in a desired pattern onto a moving carrier layer.The method allows accurate forming of a pre-determined pattern ofparticulate material clusters at high production speed and relative lowcost. Such method is particularly useful in the manufacture of absorbentcomposites for use in absorbent structure of absorbent article,preferably a disposable article, such as a feminine hygiene garment,baby diaper, baby pants and adult incontinence garment.

BACKGROUND OF THE INVENTION

Disposable absorbent articles have an absorbent structure for absorbingbodily exudates, a soft liquid-permeable top sheet on the wearer sideand a liquid-impermeable back sheet on the garment side. The absorbentstructure in between is normally made from a mixture of cellulose fibersor other fibrous substance and an absorbent polymer material. Thesefibrous substances make these absorbent articles typically quite fluffyand bulky.

In recent years there has been increasing demand for flexible, thinner,lightweight absorbent structures to resolve various problems ofmanufacturing, marketing, design, fit, wearing comfort, distribution,garbage disposal, material and energy consumption, transportation andstorage costs and the like.

The most common method currently used to meet these demands indisposable absorbent articles is to reduce the amount of cellulose fibreor other support material within and surrounding the absorbent structureand/or use larger amounts of absorbent polymer materials. Consequentlysuch absorbent articles have a smaller proportion of hydrophiliccellulose fibres and/or a higher proportion of absorbent polymersmaterials. Some of these absorbent articles may be better at storingliquid, however they are not necessarily good at absorbing anddistributing liquid when the absorbent article is actually being used.It will thus be apparent from the above that the absolute and relativeproportions of the fibrous material and absorbent polymer material areclosely linked in light of article performance. Hence there are limitson reducing the amount of hydrophilic cellulose fibre and reducing thethickness of absorbent cores.

Many attempts have been undertaken to manufacture flexible, thin,lightweight absorbent structures, consisting of a high amount ofabsorbent polymer material. In order to obtain good absorbency,distribution and retention within such absorbent structures it has foundto be important to at least partially immobilize the absorbent material.Failing to provide sufficient structural integrity results in loss offunctional performance characteristics such as coherence, absorption,distribution and/or retention and results in failures related but notlimited to for instance leakages, high rewet values, etc. On the otherhand however the presence of this physical and/or chemical interactionin between the absorbent material and the restraining material oftenalso leads to a reduced absorption, distribution and/or retentionperformance. This is especially the case when such flexible, thin,lightweight absorbent structures, consisting of an absorbent polymermaterial are placed in between multiple enveloping layers.

The larger proportion of absorbent polymer materials and relatedimmobilisation requirements in substantially cellulose free absorbentarticles may thus greatly inhibit the absorption, distribution and/orretention of liquids if inadequately managed. It will be clear that theabsolute and relative proportions of the hydrophilic cellulose fibresand absorbent polymer materials need to be tightly controlled in orderto maintain the absorbent properties of the absorbent structures.Certainly decreased absorption speed and fluid distribution are commoncauses of failure. Since such hygienic absorbent articles are generallyalso disposable and need in some instances to be worn over many hoursthey require performance in a dry state as well as in a partially andfully bodily exudates loaded state.

The ability and capacity of an absorbent polymer material to absorb,distribute and retain liquid is dependent upon the form, position and/ormanner in which the absorbent polymer material is incorporated into theabsorbent structure. Since many absorbent structures have a relativelyhomogeneous and continuous distribution of absorbent polymer material,and thus exhibit a substantial homogeneous swelling, for second, thirdand next liquid insults such absorbent layers may actually act as aliquid barrier. This gel-blocking occurs when the absorbent polymermaterial located in regions of first contact starts to increase involume as a consequence of imbibing the fluid, thereby forming ahydro-gel. Gel blocking in and adjacent a zone of the absorbent layer ofinitial liquid contact prevents liquid from rapidly dispersing orwicking past the “blocking” material into the rest of the absorbentlayer and further liquid uptake by the absorbent layer must then takeplace via for instance a diffusion process that is much slower than therate at which liquid is applied to the absorbent layer. Especially whenabsorbent polymer material concentrations are absolutely or relativelyhigh and wetted, the hydro-gel can block the initial and/or additionalfluid from reaching other still more absorbent regions of the absorbentcore, thus leading to unappreciated, underused or unused absorbentcapacity. The diminished capacity results in leakages, well before theabsorbent core is fully saturated.

Gel-blocking is even increased in thin substantially cellulose freestructures where the liquid find little or limited macroscopic voidsand/or spaces which can be used for temporary, intermediate or finalliquid storage. Also the structural volume restrictions of theseabsorbent structures lead to a further reduced absorbent performance dueto limited swelling capacity of the absorbent polymer materialincreasing the tendency to functional failures and leakages. To remedy,absorbent article designers have and typically use additional side cuffsand acquisition layers which are expensive, inefficient and can onlypartly remedy these limitations. By not completely abandoning the use ofhydrophilic fibrous materials next to the use of absorbent polymermaterials this problem can be partially resolved, however, it will beclear that in such case the absolute and relative proportions ofabsorbent materials will unwillingly be restricted and thus anythickness reduction of the absorbent structure not fully optimised.

It has been found in order to be able to keep absorbent materialscompartmentalized, restrained and/or bound within the absorbentstructures during use, it is preferred to deposit such absorbentmaterial in a predetermined and desired location, grids or patternduring the manufacturing process. It is therefore very desirable toenable the depositing of absorbent materials in a substantiallycontinuously, specific, well-defined and discretely arranged patternonto a carrier layer moving at a relatively high speed.

The present invention is not only useful for the hygiene industry (e.g.for feminine hygiene garments, baby diapers and baby pants, adultincontinence garments) but may find applications in a multitude ofindustries such as the food industry (e.g. for coffee pads), theconsumer industry (e.g. for disposable body warmers), the householdindustry (e.g. sheet formed detergent articles), construction (e.g.filter materials and insulation) as well as many other areas where it isdesirable to deposit and immobilise particle materials on to ahigh-speed carrier layer.

Multiple attempts have been made to provide methods to manufacturecomposite structures with selected regions of particulate materialsintermittently and discretely located along the length of a carrierlayer. U.S. Pat. No. 5,494,622 describes a process and apparatus forforming sandwich-like structures having clusters of absorbentparticulate material which are in a pattern chamber directly drawn anddeposited on to the surface of the carrier layer by gas flow facilitatedvacuum means. Due to the fact the pattern chamber is in contact withseveral pocket regions at a time, the filling of the pockets oftenresults in under- and/or overfilling during the forming process leadingto inefficient use of raw materials and leading to under-performingabsorbent structures, structural failures and leakages. EP1621166describes a process and apparatus for forming a substantially cellulosefree sandwich-like structure having pre-metered clusters of absorbentparticulate material held in pre-arranged patterns before beingdiscretely deposited onto the carrier layer so as to have the samepre-measured clusters located in predefined patterns before beingimmobilised and enveloped between the carrier and cover material. Whilstthe prior art attempts describe approaches to manufacture sandwichstructures and mechanism to obtain discrete particulate materialpockets, it is believed that the above methods suffer from multipledrawbacks. The prior art methods lack accuracy and repeatability of theabsorbent particulate material patterns and have unbalancedpre-metering, metering, forming and transport means. The large andexpensive pre-metering, forming and suction means required for theparticulate material transport and clustering require very specificcustomization for each product concept/size/absorbency and are veryexpensive to design, build, install and replace. These apparatus arefurthermore consuming a relative high amount of energy and takesignificant resources to operate during normal production. The webmaterials require operating within very narrow tolerances in relation toparticle material clustering and depositing and can only operate underrelatively limited production speeds, demanding large and complexmachinery and installations which are subject to excessive tear, wear,maintenance, cleaning, adjustment, etc. Also, the prior art methodsrequire the carrier layer to be at least sufficiently gas permeable,whilst it would be desired for many applications in fluid handling andstoring products such as e.g. baby diapers that the carrier layer wouldbe composed of a liquid and substantially gas impervious barrier layer.Such inefficient and ineffective methods and the complex manufacturingprocesses makes neither of the prior art methods economically,technically and/or environmentally advantageous.

Hence, there is still a need in the art for a reliable, cost-efficientand maintenance-friendly method and apparatus to consistently dispose,position and pocket particulate materials continuously in a specific,well-defined and discretely arranged pocketing pattern on the surface ofa carrier layer moving at a high production speed with limitedconsumption and/or waste of resources such as e.g. energy and rawmaterials enduring the production process.

As a result of exhaustive research to address the above-identified andrelated problems, the inventor have found a more favorable andadvantageous manufacturing process to obtain such concepts andstructures, which will be explained in greater detail down below.

SUMMARY OF THE INVENTION

As a result of exhaustive research to address the above-identified,derived and related problems, the inventor has found an optimal methodand apparatus for the manufacturing of substantially cellulose freeabsorbent structures immobilising absorbent particulate materialallowing fluid management and liquid management in dry, partially andfully liquid loaded state.

The present invention relates in essence to a method for manufacturing acomposite structure having a particulate material deposited in adepositing or printing pattern onto a carrier layer and preferablypositioned in a pocketing pattern before being immobilised via anauxiliary layer. The method comprises the steps of providing clusteringmeans essentially corresponding with the desired depositing pattern onthe moving carrier layer, driving the clustering means in the samedirection as and in close proximity to the moving carrier layer, feedinga particle material stream from a particulate material supply means anddirecting the particle material stream onto the carrier layer.Preferably an additional positioning step is provided by way of apositioning means to stabilise, position and/or reposition the absorbentmaterial in their pocketing pattern before immobilising it in thecomposite structure. The depositing pattern provided by the clusteringmeans can but does not necessarily have to correspond with thepositioning pattern formed by the positioning means. For instance incase of relative homogenous depositing patterns it will preferably notcorrespond with a discretely clustered positioning pattern.Alternatively the relative dimensions and pattern of the depositingmeans may for instance be substantially in line with the relativedimensions and pattern of the positioning means, whereby the openings ofthe depositing means are for instance larger than openings of thepositioning means to allow faster printing of the required materialswhile subsequently optimizing the somewhat blurred printing pattern toavoid the presence of any particulate materials in the attachmentregions. Alternatively the openings of the depositing means may besmaller than for instance the openings of the positioning means to allowmore accurate printing without depositing any particulate materialwithin the inter-deposit regions allowing easier pocketing. Particulatematerial such as absorbent particulate polymer material is very suitableto be used in substantially cellulose free absorbent structure for usein an absorbent article such as a disposable hygienic baby diaper orbaby made according to the present invention.

In a preferred embodiment a method for producing a composite structureis provided comprising a pattern of particulate material, said methodcomprising the steps of:

-   -   a—providing at least one essentially endless layer as carrier        layer and/or auxiliary layer    -   b—providing an essentially endless support means for said        carrier layer,    -   c—positioning said carrier layer over said support means,        whereby said carrier layer is in contact with the contact        surface of said support means, and whereby the relative speed        between said carrier layer, contact surface of said carrier        support means and the clustering means is essentially zero;    -   d—providing a particulate material stream from a particle        material supply means;    -   e—directing the particulate material through the perforation of        a clustering means;    -   g—combining said carrier layer and said auxiliary layer with        said particulate material sandwiched there between;    -   characterized in that,    -   h—said clustering means guide said particulate material towards        the carrier layer thereby creating a printing pattern of        particulate material;    -   I—said printing pattern being positioned by positioning means        thereby forming a pocket pattern of particulate material on the        carrier material;    -   j—and in that the positioning means substantially evacuate        particulate material from the inter-pocket pattern zones into        the pocket pattern before joining the carrier layer and        auxiliary layer to form a pattern of particulate material.

In a preferred embodiment according to the present invention anapparatus is provided for producing a composite structure comprising apattern of particulate material, said apparatus comprising:

-   -   a—a clustering means having a desired perforation pattern    -   b—a particulate material supplying means positioned to provide        particulate materials into the inlet regions of the perforation        of said clustering means;    -   c—a carrier layer supplying means for providing a carrier layer;        support means for moving said carrier layer in close proximity        to the outlet regions of the clustering means;    -   d—a positioning means having a desired pocketing pattern    -   e—transport means for moving said carrier layer with particulate        material pattern towards attachment means.

In a preferred embodiment of the invention the clustering means withdesired perforation pattern is incorporated into an essentially endlessrotating drum, the clustering means can be mounted replaceably onto therotating drum or can be unitary therewith. The carrier layer ispositioned over a substantially endless support means at a carrier speedrelative to a fixed frame, whereby the carrier layer is in contact withthe support means and whereby the relative speed between carrier layer,the support means and the clustering means and/or drum is preferablyessentially zero. The endless support means can have positioning meansmounted thereon or can be unitary therewith. A particulate material isprovided by a particulate material supply means and the particulatematerial stream is essentially directed towards the clustering means.The directed particulate material is collected by the inlet regions ofthe perforations of the clustering means and at least partially held inthe outlet region (and/or inlet regions) of the perforations of theclustering means until evacuated. The carrier layer is preferablysupported over at least part of the major support means surface areawhile the particulate material caught and held in the perforations isdeposited onto the carrier material.

According to an alternative embodiment of the invention a particulatematerial is provided via a stationary clustering means located in closeproximity of the moving carrier layer. In this alternative embodimentthe carrier layer is positioned over a substantially endless supportmeans at a carrier speed relative to the fixed frame, whereby therelative speed between carrier layer and the clustering means issubstantially different from zero. In one embodiment the particulatematerial stream is homogenously directed towards the positioning means,while in another embodiment the particulate material stream isheterogeneously directed via clustering. The homogenous or heterogeneousparticulate material will during or after deposit by the depositingmeans preferably be stabilized, positioned and/or repositioned bypositioning means. The carrier layer is preferably supported over atleast part of the major support means surface area while the particulatematerial is directed towards the carrier material.

In an embodiment according to the invention, the resulting compositestructure of a carrier layer with discretely deposited (and preferablypositioned) particulate material clusters thereon, is complemented withan auxiliary layer, such as for instance non-woven, tissue, paper,thermoplastic material and the like and/or affixed by attachment means,such as for instance glue, bonds, joints and the like, with theparticulate material clusters pocketed there between so as to obtain animmobilized sandwich structure usable in the form of an absorbentstructure.

In a preferred embodiment the absorbent structure immobilizes, retainsand/or restrains the particulate material and the attachments seal, bondand/or join at least part of the outer layers of the composite structuretogether via ultrasonic bonding, thermo-bonding, pressure-bonding and/orglue-bonding means. These attachments preferably form and/or definepockets which contain particulate material, whereby the attachmentregions comprise essentially and preferably no particulate material.Preferably the absence of an excess or the complete elimination ofsynthetic immobilisation admixtures (e.g. adhesive and binders, such asthermoplastic glues and webs) used for covering, restraining or bondingabsorbent polymers makes the structure technically, environmentally andeconomically very favourable. In an alternative embodiment however, thecomposite structure is covered with such thermoplastic materials, glues,binders and/or adhesives to fixate, pocket, encapsulate, bind and/orjoin these particulate material clusters to and/or in between one ormore layers. Additional materials and/or layers to provide extrafunctional and/or structural advantages such as strength, acquisition,absorption, distribution, transport, retention, etc. may also beincorporated.

In a preferred embodiment according to the invention, a process forproviding a structure comprising of a carrier layer, a particulatematerial and an auxiliary layer is provided, whereby the particulatematerial is at least partially enclosed by a carrier and auxiliary layerso as to form an composite structure, comprising the steps of prior tojoining the carrier layer to the auxiliary layer positioning thedeposited particulate material through a positioning means, preferablybeing airflows. In one embodiment, the particulate material is depositedsubstantially homogeneously on the carrier layer prior to subsequentlypositioning it via the positioning means to discretely andheterogeneously positioned particulate material clusters. In a preferredembodiment, the particulate material comprises absorbent polymermaterial for body exudates and/or skin care material such as ionexchange resins, deodorant, anti-microbial agents, binder particles orother beneficial particles.

An absorbent structure manufactured according to this preferredembodiment of the invention has attachments characterized by improvedattachment properties. This is advantageous as it provides increasedefficiency and effectiveness of the used attachment means, therebyincreasing attachment quality, quantity and/or utilisation of attachmentenergy or materials which is crucial in the high speed and low costmanufacturing of absorbent articles containing such absorbent structuresin light specified absorption, distribution, retention performance whileminimizing rewet, leakages and structural failures.

During the depositing process, the particulate material is directed tothe carrier layer. If the particulate material is spread homogeneously,the probability that a small piece of particulate material is positionedin an area which is intended to serve as an attachment area between thecarrier layer and the auxiliary layer, is given by P_(normal)=B/(A+B),where “B” is the attachment area on a piece of the carrier layer and “A”is the area on the same piece of the carrier layer which is not to beattached to the auxiliary material. According to a preferred methodaccording to the present invention particulate material isnon-homogeneously deposited prior to attaching the carrier layer to theauxiliary layer, such that the probability P_(inv) of a smaller piece ofparticulate material is deposited in an attachment area is smaller thanP_(normal): P_(inv)<P_(normal), preferably P_(inv)<0.5*P_(normal), morepreferably P_(inv)<0.1*P_(normal), even more preferablyP_(inv)<0.05*P_(normal), still even more preferablyP_(inv)<0.01*P_(norrnal), most preferably P_(inv)<0.001*P_(normal).Decreasing the possibility P_(inv) is advantageous for the attachmentprocess, since the presence of particulate material in or on theattachment area may lead to a less strong attachment between carrierlayer and auxiliary layer. Obviously the more accurate the depositingrequirements of the particulate materials will have to be the slowerand/or more difficult the positioning step will be during industrialmanufacturing of composite structures according to the presentinvention. Hence the favourable positioning means allow for a lessaccurate depositing as via this positioning step the incorrectly orinaccurately deposited particulate materials are repositioned towardstheir intended position by way positioning and repositioning of theparticulate materials. Additional correctly and accurately depositedparticulate materials are stabilized to be kept in their intendedposition by way of these same positioning means allowing correctpocketing and immobilisation of all particulate materials withoutinferior attachment properties imparted by migrated, misplaced or lostparticulate materials.

According to another aspect of the present invention an apparatus forproducing a composite structure comprising particulate material clustersthere between is provided. Said apparatus comprises a clustering meanshaving a desired depositing pattern, a particulate material supplyingmeans positioned to provide particulate materials into the inlet regionsof the perforations of said clustering means, a carrier layer supplyingmeans for providing a carrier layer, support means for moving saidcarrier layer in close proximity to the outlet regions of the clusteringmeans and transport means for moving said carrier layer with particulatematerial clusters away from the clustering means. Preferably furtherpositioning means are foreseen to position the absorbent material intheir optimal pocket position before immobilising them in the compositestructure. The positioning means can be mounted on or can be unitarywith the support means and/or transport means.

The clustering means are preferably arranged to catch, collect, hold anddeposit the particulate materials from the particulate material streamas provided by the particulate supply means. The perforations within theclustering means are designed so as to catch and collect the particulatematerial stream by way of the inlet regions, and preferably converge theparticulate materials towards the outlet regions so as to accumulate andbuild up particulate material clusters within the perforations ready fordeposit onto the carrier layer, preferably in discrete printing patternsof particulate material clusters. It will be apparent that theperforations of the clustering means can be made up from all availablealternatives known from the art such as hollow rectangles, cones, tubesand any other suitable format to direct the particulate material to thecarrier layer.

The support means brings the carrier layer into a depositing positionof, preferably in close proximity to, most preferably in contact with,the outlet regions of the perforations of the clustering means.Preferably a selected level of pressure contact in between the depositsurface of the carrier layer and the outer contact surface of theclustering means is provided, so as to lock the discrete particulatematerial clusters until deposited onto the deposit surface of thecarrier layer. In an alternative embodiment, no substantial pressurecontact in between the deposit surface of the carrier layer and theouter contact surface of the clustering means is provided, and theparticulate material provided via the particulate material stream isimmediately caught, collected and deposited upon the carrier layer.Preferably additional positioning means are foreseen to stabilise,position and/or reposition the deposited particulate material clustersin their final pocketing position and pattern before being immobilized.A transport means moves the carrier layer and the particulate materialsaway.

In a preferred embodiment the particulate material clusters deposited,and preferably positioned, onto the carrier layer are covered by anauxiliary layer via a covering means so as to form for instance anabsorbent polymer material area. In a more preferred embodiment, theparticulate material clusters from the composite structure arerelatively immobilised, bound, joined and/or otherwise restrained inbetween a carrier layer and any suitable auxiliary layer. Preferably,attachment means leading to a composite sandwich structure of a carrierlayer and auxiliary layer with particulate material clusters enclosedand/or immobilised, bound, join and/or restrained there between in theform of pockets or compartment are provided.

Preferably the particulate material supply means comprises a vibrating,coiling and/or turning means so as to accurately, continuously andcontrollably provide the required particulate material amounts, sizesand/or speeds towards the clustering means. It is furthermore preferred,that the particulate material is being transported in between suchvibrating, coiling and/or turning means and the clustering means by wayof a feeding tube means, which can alternatively be arranged with gaspressure means to guide and direct the particulate material stream tothe inlet regions of the clustering means. In a preferred embodiment,the feeding tube is substantially longitudinal, vertically and/orconverging and the particulate material has substantial weight so thatone can use gravity to transport the particles through the feeding tubeinto the clustering means. However, additional conveyer means such asmechanical (such as airflows), electro-magnetic (such as magnets in casethe particles interact with a magnetic field), electro-static (such asparticulate material and/or conveyer charging) and/or other means can beused to help convey particulate material stream towards the clusteringmeans.

In a preferred embodiment, a dosing means of a volumetric, gravimetricor other type is used so as to control the quantity, size and/or speedof particles entering the feeding tube means is provided. It is furtherpreferred that the particulate material stream can be redirected viacontrol means into removing means so as to be moved again towards theparticulate supply means via recovery tubing means for re-use and/orless preferably guided out of the production system via collection meansto be moved towards separate storage facilities for later usage and/ordisposal in case irreparably damaged, contaminated, spoiled and/orrendered unusable.

In a preferred embodiment, the clustering means are unitary with asubstantially endless rotating drum, preferably having a cylinder-likeouter shell. In a preferred embodiment an endless rotating drum withreplaceable, customisable and/or adjustable clustering means isprovided. Alternatively the clustering means are stationary clusteringmeans. The clustering means are in line with the opening of the feedingtube means thereby directing the particulate materials to fall, beguided, directed, pushed and/or vacuumed through the respective inletregions and/or outlet regions of the perforation pattern of theclustering means to obtain the desired depositing or printing pattern.It is understood that the clustering means can have any sort and numberof perforations and patterns, whereby the amount of perforations goesfrom at least one perforation to any suitable numbers of perforations inlight of the envisaged composite structure. In case one perforation itsdimension may be similar to feeding tube.

It is preferred to under-fill (or, eventually ‘right-fill’) theperforations of the clustering means. Using a particle material supplymeans with a preferably gravimetric dosing system in combination with afeeding tube means such as a tube, pipe or conveyer of the rightdimensions and shape will then ensure that the proper weights aresupplied, gathered in the perforations and deposited by the outletregions so as to form the desired printing pattern of particulatematerial clusters as stipulated by the perforation pattern of theclustering means.

In a preferred embodiment, the inlet regions are of a funnel-like shapewith steep slopes separated from one another by sharp ridges so nosubstantial amounts of particulate materials remain caught in betweenthe inlet regions and/or on the slopes of the inlet regions, but arereadily transported towards the outlet regions for scheduled deposit onthe carrier material. In a preferred embodiment, a combination of largerand smaller inlet regions and outer regions are provided leading to morehomogenous, heterogeneous or complex perforation patterns.

Preferably the void volume of the perforations is larger than thevolumes of particulate material one wants to print, to preventoverfilling of the clustering means during the production process. Inthis case of correctly designed clustering means and a fully,effectively and efficiently working apparatus one can also greatlyincrease accuracy and reliability of the manufacturing process andthereby also eliminating the need for a sweeping means, thus optimisingraw material usage, limiting investment cost and reducing maintenancecost. However in case required, any ‘overfill’, migration and/ormisplacement of particulate material can be guided and/or redirected viasweeping means, such as scrapers, brushes, air blow, vacuum suction,etc, into one or more available inlet regions of the cluster meansand/or be guided into recovery means or collection means so as to bemoved away from the clustering means for re-use, collection and/ordisposal. This redirecting greatly increases process efficiency.

As also described in EP priority application 10447020.8 and herebyincorporated by reference, an absorbent sandwich-like structure isprovided which comprises a distribution layer with an absorbent capacityand an immobilisation layer which joins to the distribution layer todefine compartments there between containing intermediate absorbentmaterial. In particular an absorbent structure for use in an absorbentarticle comprises a distribution layer having an absorbent capacity ofat least about 5 g/m², an immobilisation layer which is joined to thedistribution layer to define compartments there between, and anabsorbent material held in at least one of the compartments, whereinsaid absorbent material comprises an absorbent polymer material and fromzero to an amount less than about 40 weight percent absorbent fibrousmaterial, based on the weight of absorbent polymer material. Theabsorbent structure provides in particular an increased fluidcommunication structure including better adsorption and dispersion inand between the absorbent polymer material pockets, due to theadditional wicking and mass flow of liquids caused by the distributionlayer, limiting gel blocking, reducing rewet and minimizing leakages. Itfurther provides for a method and apparatus to produce such absorbentstructures at high production speed with low energy and raw materialconsumption.

As also described in EP priority application 10447021.6 and herebyincorporated by reference, an absorbent sandwich-like structure isprovided which comprises a substantially liquid-impermeable wickinglayer and an immobilisation layer which joins to the wicking layer todefine compartments there between containing intermediate absorbentmaterial. In particular an absorbent structure for use in an absorbentarticle comprises a substantially liquid-impermeable wicking layer, andan immobilisation layer which is joined to the substantiallyliquid-impermeable wicking layer to define compartments there between,and an absorbent material held in at least one of the compartments,wherein said absorbent material comprises an absorbent polymer material,and from zero to an amount less than about 40 weight percent absorbentfibrous material, based on the weight of absorbent polymer material. Thesubstantially liquid-impermeable wicking layer allows unbound liquidssuch as water, urine and/or other bodily exudates to more easily spreadout, which allows better distribution and transport so as to wet theside and lower sides of the absorbent polymer materials within thepockets. It ensure lower rewet values, less leakage risk and lesssurface wetness and thus increased reliability of the overall structure.It further provides for a method and apparatus to produce such absorbentstructures at high production speed with low energy and raw materialconsumption.

As also described in EP priority application 10447022.4 and herebyincorporated by reference, an absorbent sandwich-like structure isprovided which comprises a carrier layer, an auxiliary layer and anintermediate absorbent particulate material there between whereinsubstantially primary attachments and substantially secondaryattachments join the carrier layer and auxiliary layer together, wherebythe secondary attachments are loosened as a result of exposing theabsorbent structure to liquid whereas the primary attachments remainsubstantially intact. It further provides for a method and apparatus toproduce such absorbent structures at high production speed with lowenergy and raw material consumption.

As also described in EP priority application 10447023.2 and herebyincorporated by reference, an absorbent sandwich-like structure isprovided which comprises a carrier layer, an auxiliary layer and anintermediate absorbent material there between wherein substantiallypermanent primary attachments and substantially temporary secondaryattachments join the carrier layer and auxiliary layer together, wherebythe absorbent structure is made to in-homogeneously swell as a result ofexposing the absorbent structure to liquid to form a liquid-managingsurface structure. It further provides for a method and apparatus toproduce such absorbent structures at high production speed with lowenergy and raw material consumption.

As also described in EP priority application 10447024.0 and herebyincorporated by reference, a method and apparatus is provided forforming a sandwich-like structure, by depositing particulate material ina desired pattern onto a moving carrier layer. In particular a methodfor depositing particulate material in a desired pattern onto a movingcarrier layer is provided, which provides a clustering means withperforations corresponding to a desired pattern, driving the clusteringmeans in the same direction as and in close proximity to the movingcarrier layer, feeding a particle material stream from a particulatematerial supply means and directing the particle material stream throughthe clustering means onto the carrier layer. Preferably the particulatematerials are clustered via the inlet regions of the perforations andreleased via the outlet regions of the clustering means. The methodallows accurate forming of a pre-determined pattern of particulatematerial clusters at high production speed, with reduced raw materialusage and relative low cost. It furthermore provides the improved thin,flexible, lightweight particulate material absorbent structures withdiscretely deposited particulate material clusters thereon, complementedwith an auxiliary layer, such as for instance non-woven, tissue, paper,thermoplastic material and the like and/or affixed by attachment means,such as for instance glue, bonds, joints and the like, with particulatematerial clusters relatively immobilized there between so as to obtain asandwich structure usable in the form of an absorbent structure.

As also described in EP priority application 10447027 and herebyincorporated by reference, a method and apparatus is provided forforming a sandwich-like structure, by positioning particulate materialin a desired pattern onto a moving carrier layer. In particular a methodfor positioning particulate material in a desired pattern onto a movingcarrier layer is provided, providing a first material, an intermediatematerial and a second material, whereby prior to joining the firstmaterial to the second material, the distribution of the intermediateparticulate material is altered through an airflow. In a preferredembodiment the intermediate particulate material is providedsubstantially homogeneously on the first material prior to applying thepositioning airflow. When the intermediate material is undesirable inthe attachment area, the method describes the use of airflows, resultingfrom blowing and/or suction holes to evacuate the intermediate materialfrom the attachment area prior to or during bonding, leading to improvedand controllable attachment properties, thus increasing attachmentquality and utilisation of energy or materials. It furthermore providesimproved thin, flexible, lightweight absorbent particulate structures.

The method and apparatus according to preferred embodiments of theinvention leads to highly appreciated thin, flexible and/or light-weightabsorbent structures which are economically, environmentally,technically and/or commercially advantageous, not in the least sincethey are obtained without the need for substantial and bulky amounts offibrous absorbent materials such as fluff and wood pulp (allowing“fluffless” advertisement claims) and are not using substantial andexpensive amounts of glue, binder, adhesive and/or other thermoplasticmaterials (allowing “glueless” advertisement claims). This isunprecedented within the prior art.

BRIEF DESCRIPTION OF FIGURES

FIG. 1A-D provides cross-sectional schematic illustrations of absorbentstructures made according to embodiments of the invention.

FIG. 2 provides a top view schematic illustration of an absorbentstructure made according to an embodiment of the invention.

FIG. 3 provides a top view schematic illustration of differently locatedand sized clusters of absorbent material obtainable according to anembodiment of the invention.

FIG. 4 provides a top view schematic illustration of an absorbentstructure in a partially wetted state made according to an embodiment ofthe invention, indicating substantial permanent primary attachments; andthe gradual release by the still joined and already loosened temporarysecondary attachments.

FIG. 5 provides top view schematic illustrations of an absorbentstructure made according to an embodiment of the invention indicatingdifferent cluster patterns.

FIG. 6 provides a schematic process diagram for carrying out theinvention.

FIG. 7 provides a schematic top view illustration of a clustering meansmounted onto a drum according to an embodiment of the invention.

FIG. 8 provides a schematic top view illustration of a clustering meansaccording to an embodiment of the invention.

FIG. 9 provides schematic top view illustration of a carrier layer withdeposited patterns and positioning patterns according to an embodimentof the invention.

FIG. 10 provides a cross-sectional schematic illustration of aclustering means according to an embodiment of the present invention.

FIG. 11 provides a cross-sectional schematic illustration of a depositedparticulate material cluster according to an embodiment of the presentinvention.

FIG. 12 provides schematic enlarged sectional view of a part of theequipment for the process as shown in FIG. 13.

FIG. 13 provides schematic illustration of an apparatus for carrying outthe invention according to an embodiment of the invention.

FIG. 14 provides a cross-sectional schematic illustration of anattachment process using airflows according to an embodiment of theinvention.

FIG. 15 provides a cross-sectional schematic illustration of anattachment process using airflows according to another embodiment of theinvention.

FIG. 16 provides a cross-sectional schematic illustration of anattachment process using airflows in a combination with blowing andsuction holes according to another embodiment of the invention.

FIG. 17 provides a cross-sectional schematic illustration of anattachment process using airflows according to another embodiment of theinvention.

FIG. 18 provides a top view schematic illustration of an attachmentprocess using airflows according to another embodiment of the inventionshowing blowing and/or suction holes.

FIG. 19 provides a cross-sectional schematic illustration of anotherattachment process using airflows according to another embodiment of theinvention.

FIG. 20 provides a top view schematic illustration of an positioningmeans according to an embodiment of the invention using airflows incombination with a perforated mask.

FIG. 21 provides a cross-sectional schematic illustration of a processaccording to an embodiment of the invention for manufacturing acomposite structure of with enclosed particulate material by usingairflows generated by means of additional positioning means.

FIG. 22 provides a top plan view of a diaper as a preferred embodimentof an absorbent article comprising an absorbent structure obtainable bya method and apparatus according to an embodiment of present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method and apparatus for creatingcomposite structures comprising particulate material, preferablyabsorbent particulate material such as absorbent polymer materials, morepreferably absorbent particulate polymer material; preferably clustered,enveloped and/or immobilised in between a carrier layer and auxiliarylayer, possibly via primary and secondary attachment means, so as toform discrete and predetermined pocketing patterns of particulatematerial sheets for use in absorbent products, preferably a disposableabsorbent article from the personal hygiene industry, such as femininehygiene garments, baby diapers and pants and adult incontinencegarments.

Unless otherwise defined, all terms used in disclosing the invention,including technical and scientific terms, have the meaning as commonlyunderstood by one of ordinary skill in the art to which this inventionbelongs. By means of further guidance, term definitions are included tobetter appreciate the teaching of the present invention.

As used herein, the following terms have the following meanings:

“A”, “an”, and “the” as used herein refers to both singular and pluralreferents unless the context clearly dictates otherwise. By way ofexample, “a compartment” refers to one or more than one compartment.

“About” as used herein referring to a measurable value such as aparameter, an amount, a temporal duration, and the like, is meant toencompass variations of +/−20% or less, preferably +/−10% or less, morepreferably +/−5% or less, even more preferably +/−1% or less, and stillmore preferably +/−0.1% or less of and from the specified value, insofarsuch variations are appropriate to perform in the disclosed invention.However, it is to be understood that the value to which the modifier“about” refers is itself also specifically disclosed.

“Absorbent article”, “absorbent garment”, “absorbing article”,“absorbing garment”, and the like as used herein are usedinterchangeably and refer to devices that absorb and contain bodilyexudates, and more specifically, refers to devices that are placedagainst or in proximity to the body of the wearer to absorb and containthe various liquids discharged from the body.

Absorbent articles include but are not limited to feminine hygienegarments, baby diapers and pants, adult incontinence garments, variousdiaper and pants holders, liners, towels, absorbent inserts and thelike.

“Absorbent component” as used herein refers to a structural constituentof an absorbent structure, e.g., a piece of an absorbent core, such asone of multiple pieces in a multi-piece absorbent core.

“Absorbent element” as used herein refers to a part of a functionalconstituent of an absorbent structure, e.g., a liquid acquisition layer,a liquid distribution layer, or a liquid storage layer formed of amaterial or materials having particular liquid handling characteristicssuitable for the specific function.

“Absorbent insert” as used herein refers to a device adapted forinsertion into an absorbent article and to serve as an absorbentstructure when so inserted.

“Absorbent layer” as used herein refers to a term referring to adiscrete, identifiable sheet-like or web-like element of an absorbentstructure which may remain detached and relatively movable with respectto another such element or may be attached or joined so as to remainpermanently associated with another such element. Each absorbent layermay itself include a laminate or combination of several layers, sheetsand/or webs of similar or diverse compositions.

“Absorbent polymer material”, “absorbent gelling material”, “AGM”,“superabsorbent”, “superabsorbent material”, “super absorbent polymer”,“SAP” and the like as used herein are used interchangeably and refer toany suitable particulate (e.g., flaked, particulate, granular, orpowdered) or fibrous cross linked polymeric materials that can absorb atleast 5 times and preferably at least about 10 times or more its weightof an aqueous 0.9% saline solution as measured using the CentrifugeRetention Capacity test (EDANA 441.2-01).

“Absorbent polymer material area” as used herein refers to the area ofthe absorbent structure wherein adjacent layers are separated by amultiplicity of absorbent polymer material. Incidental contact areasbetween these adjacent layers within the absorbent particulate polymermaterial area may be intentional (e.g. bond area's) or unintentional(e.g. manufacturing artefacts).

“Absorbent particulate polymer material” as used herein refers to anabsorbent polymer material which is in particulate form such as powders,granules, flakes and the like so as to be flowable in the dry state.

“Absorbent structure” as used herein refers to those elements of anabsorbent article comprising material or a combination of materialssuitable to absorb, distribute and retain bodily exudates.

“Absorption” as used herein refers to the process by which a liquid istaken up within a material.

“Acquisition layer”, “acquisition region”, “acquisition surface” or“acquisition material” and the like as used herein refer to a layerhaving a faster liquid uptake capability.

“Absorbency” is the ability of a material to take up fluids by variousmeans including capillary, osmotic, solvent, chemical or other action.

“Adult incontinence garment” as used herein refers to absorbent articlesintended to be worn by incontinent adults, for absorbing and containingbodily exudates.

“Adhesion” as used herein refers to the force that holds differentmaterials together at their interface.

“Adhesive” as used herein refers to a material, which may or may not beflowable in solution or when heated, that is used to bond materialstogether.

“Adsorption” as used herein refers to the process by which a liquid istaken up by the surface of a material.

“Airlaying” as used herein refers to forming a web by dispersing fibresor particles in an air stream and condensing them from the air streamonto a moving screen by means of a pressure or vacuum; a web of fibresproduced by air laying is herein referred to an “airlaid”; an airlaidweb bonded by one or more techniques to provide fabric integrity isherein referred to an “airlaid non-woven”.

“Apparent density”, “density” and like as used herein refers to thebasis weight of the sample divided by the calliper with appropriate unitconversions incorporated therein. Apparent density used herein has theunit g/cm³.

“Attach”, “attached” and “attachment” as used herein are synonymous withtheir counterparts of the terms “fasten”, “affix”, “secure”, “bind”,“join” and “link”.

“Baby diaper” as used herein refers to absorbent articles intended to beworn by children, for absorbing and containing bodily exudates which theuser draws up between the legs and fastens about the waist of thewearer.

“Baby pants” as used herein refers to absorbent articles marketed foruse in transitioning children from diapers to underwear intended tocover the lower torso of children, so as to absorb and contain bodyexudates which article is generally configured like a panty garment andmanufactured with a completed waist encircling portion, therebyeliminating the need for the user to fasten the article about the waistof the wearer.

“Back region” as used herein refers to the portion of an absorbentarticle or part thereof that is intended to be positioned proximate theback of a wearer.

“Backing” as used herein refers to a web or other material that supportsand reinforces the back of a product.

“Basis weight” is the weight per unit area of a sample reported in gramsper square meter, g/m² or gsm.

“Bodily exudates”, “body exudates”, “bodily fluids”, “body fluids”,“bodily discharges”, “body discharges”, “liquids” and the like as usedherein are used interchangeably and refer to, but are not limited tourine, blood, vaginal discharges, breast milk, sweats and faecal matter.

“Binder”, “adhesive”, “glue”, “resins”, “plastics” and the like as usedherein are used interchangeably and refer to substances, generally in asolid form (e.g. powder, film, fibre) or as a foam, or in a liquid form(e.g. emulsion, dispersion, solution) used for example by way ofimpregnation, spraying, printing, foam application and the like used forattaching or bonding functional and/or structural components, elementsand materials, for example including heat and/or pressure sensitiveadhesives, hot-melts, heat activated adhesives, thermoplastic materials,chemical activated adhesives/solvents, curable materials and the like.

“Bond strength” as used herein refers to the amount of adhesion betweenbonded surfaces. It is a measure of the stress required to separate alayer of material from the base to which it is bonded.

“Capillary action”, “capillarity”, or “capillary motion” and the like asused herein are used to refer to the phenomena of the flow of liquidthrough porous media.

“Chassis” as used herein refers to a foundational constituent of anabsorbent article upon which the remainder of the structure of thearticle is built up or overlaid, e.g., in a diaper, the structuralelements that give the diaper the form of briefs or pants whenconfigured for wearing, such as a backsheet, a topsheet, or acombination of a topsheet and a backsheet.

“Cellulose fibres” as used herein refers to naturally occurring fibresbased on cellulose, such as, for example cotton, linen, etc; wood pulpfibres are one example of cellulose fibres; man-made fibres derived fromcellulose, such as regenerated cellulose (rayon), or partially or fullyacetylated cellulose derivatives (e.g. cellulose acetate or triacetate)are also considered as cellulose fibres.

“Cluster” or the like as used herein refers to an agglomeration ofparticles and/or fibres.

“Chemically stiffened fibres”, chemically modified fibres”, “chemicallycross-linked fibres”, “curly fibres” and the like as used herein areused interchangeably and refer to any fibres which have been stiffenedby chemical means to increase stiffness of the fibres under both dry andaqueous conditions, for example by way of addition of chemicalstiffening agents (e.g. by coating, impregnating, etc), altering thechemical structure of the fibres themselves (e.g. by cross-linkingpolymer chains, etc) and the like.

“Cohesion” as used herein refers to the resistance of similar materialsto be separated from each other.

“Compartment” as used herein refers to chambers, cavities, pockets andthe like.

“Comprise,” “comprising,” and “comprises” and “comprised of” as usedherein are synonymous with “include”, “including”, “includes” or“contain”, “containing”, “contains” and are inclusive or open-endedterms that specify the presence of what follows e.g. a component and donot exclude or preclude the presence of additional, non-recitedcomponents, features, elements, members, steps, known in the art ordisclosed therein.

“Coverstock” as used herein refers to a lightweight non-woven materialused to contain and conceal an underlying absorbent core material;examples are the facing layer or materials that cover the absorbentcores of feminine hygiene garments, baby diapers and pants and adultincontinence garments.

“Crotch region” of an absorbent article as used herein refers to about50% of the absorbent article's total length (i.e., in the y-dimension),where the crotch point is located in the longitudinal centre of thecrotch region. That is, the crotch region is determined by firstlocating the crotch point of the absorbent article, and then measuringforward and backward a distance of 25% of the absorbent article's totallength.

“Cross direction (CD)”, “lateral” or “transverse” and the like as usedherein are used interchangeably and refer to a direction which isorthogonal to the longitudinal direction and includes directions within±45° of the transversal direction.

“Curing” as used herein refers to a process by which resins, binders orplastics are set into or onto fabrics, usually by heating, to cause themto stay in place; the setting may occur by removing solvent or bycross-linking so as to make them insoluble.

“Diaper”, “conventional diaper”, “diaper-like”, “diaper-like garment”and the like as used herein are used interchangeably and refer todisposable absorbent articles, which typically include a front waistportion and a back waist portion which may be releasably connected aboutthe hips of the wearer during use by conventional fasteners such asadhesive tape fasteners or hook and loop type fasteners. In use, thearticle is positioned between the legs of the wearer and the fastenersare releasably attached to secure the back waist portion to the frontwaist portion of the diaper, thereby securing the diaper about the waistof the wearer. The front waist portion and a back waist portion areconnected by relatively non-stretchable or stretchable members (the term“stretchable” as used herein refers to materials that are extensiblewhen forces are applied to the material, and offer some resistance toextension). Hence, such articles are generally not configured to bepulled up or down over the hips of the wearer when the fasteners areattached.

“Disposable” is used herein to describe articles that are generally notintended to be laundered or otherwise restored or reused (i.e., they areintended to be discarded after a single use and, preferably, to berecycled, composted or otherwise disposed of in an environmentallycompatible manner).

“Distribution layer”, “distribution region”, “distribution surface” or“distribution material” and the like as used herein are usedinterchangeably and refer to a layer having a larger capacity inwicking, dispersing and distributing liquids.

“Dry laying” as used herein refers to a process for making a non-wovenweb from dry fibre; these terms apply to the formation of carded webs,as well as to the air laying formation of random webs; a web of fibresproduced by dry laying is herein referred to as a “drylaid”; a drylaidweb bonded by one or more techniques to provide fabric integrity isherein referred to a “drylaid non-woven”.

“Dry strength” as used herein refers to the strength of an adhesivejoint determined in dry state conditions, immediately after drying underspecified conditions or after a period of conditioning in the standardlaboratory atmosphere.

“Fabric” as used herein refers to a sheet structure made from fibres,filaments and/or yarns.

“Feminine hygiene garments” as used herein refer to absorbent hygienearticles intended to be worn by woman, for absorbing and containing bodyexudates.

“Fibre” as used herein refers to the basic threadlike structure fromwhich non-woven, yarns and textiles are made. It differs from a particleby having a length at least 4 times its width; “Natural fibres” areeither of animal (wool, silk), vegetable (cotton, flax, jute) or mineral(asbestos) origin, while “Man-made fibres” may be either polymerssynthesised from chemical compounds (polyester, polypropylene, nylon,acrylic etc.) or modified natural polymers (rayon, acetate) or mineral(glass). “Fibre” and “filament” are used interchangeably.

“Film”, “foil” and the like as used herein are used interchangeably andrefer to a thin sheet of essentially non-absorbent material such asplastic or closed foams. In this invention it particularly refers tomaterials that do not correspond to non-woven.

“Fluff pulp” as used herein refers to wood pulp specially prepared to bedry laid.

“Front region” as used herein refers to the portion of an absorbentarticle or part thereof that is intended to be positioned proximate thefront of a wearer.

“Garment facing layer” as used herein refers to elements of the chassisthat form the outer surface of the absorbent article, such as the backsheet, the side panels, the waist fasteners, and the like, when suchelements are present.

“Heat activated adhesive” as used herein refers to a dry adhesive thatis rendered tacky or fluid by application of heat or heat and pressureto the assembly.

“Heat sealing adhesive” as used herein refers to a thermoplasticadhesive which is melted between the adherent surfaces by heatapplication to one or both of the adjacent adherent surfaces.

“Highloft” as used herein refers to general term of low density, thickor bulky fabrics.

“Hot-melt adhesive” as used herein refers to a solid material that meltsquickly upon heating, then sets to a firm bond upon cooling; used foralmost instantaneous bonding.

“Hydrophilic” as used herein refers to having an affinity for beingwetted by water or for absorbing water.

“Hydrophobic” as used herein refers to lacking the affinity for beingwetted by water or for absorbing water.

“Immobilisation layer” as used herein refers to a layer able to beapplied to the particulate material with the intent to immobilize, bond,join and/or restrain particulate material.

“Join”, “joined” and “joining” as used herein refers to encompassingconfigurations wherein an element is directly secured to another elementby affixing the element directly to the other element, as well asconfigurations wherein the element is indirectly secured to the otherelement by affixing the element to an intermediate member or memberswhich in turn is or are affixed to the other element.

“Knitting” as used herein refers to the technique for interlocking loopsof fibres with needles or similar devices.

“Layer” refers to identifiable components of the absorbent article, andany part referred to as a “layer” may actually comprise a laminate orcombination of several sheets or webs of the requisite type ofmaterials. As used herein, the term “layer” includes the terms “layers”and “layered.” “Upper” refers to the layer of the absorbent articlewhich is nearest to and faces the wearer facing layer; conversely, theterm “lower” refers to the layer of the absorbent article which isnearest to and faces the garment facing layer. “Layer” is threedimensional structure with a x dimension width, y dimension length, andz-dimensions thickness or calliper, said x-y dimensions beingsubstantially in the plane of the article, however it should be notedthat the various members, layers, and structures of absorbent articlesaccording to the present invention may or may not be generally planar innature, and may be shaped or profiled in any desired configuration.

“Machine direction (MD)”, “longitudinal” and the like as used herein areused interchangeably and refer to a direction running parallel to themaximum linear dimension of the structure and includes directions within±45° of the longitudinal direction.

“Major surface” as used herein refers to a term used to describe thesurfaces of greatest extent of a generally planar or sheet-likestructural element and to distinguish these surfaces from the minorsurfaces of the end edges and the side edges, i.e., in an element havinga length, a width, and a thickness, the thickness being the smallest ofthe three dimensions, the major surfaces are those defined by the lengthand the width and thus having the greatest extent.

“Mass flow” as used herein refers to the flow of a liquid from oneabsorbent element or component to another absorbent element or componentby channel flow action.

“Mechanical bonding” as used herein refers to a method of bonding fibresby entangling them. This can be achieved by needling, stitching withfibres or by the use of high-pressure air or water jets and the like.

“Non-woven” as used herein refers to manufactured sheet, web or batt ofdirectionally or randomly orientated fibres, bonded by friction, and/orcohesion and/or adhesion, excluding paper and products which are woven,knitted, tufted, stitch-bonded incorporating binding yarns or filaments,or felted by wet-milling, whether or not additionally needled. Thefibres may be of natural or man-made origin and may be staple orcontinuous filaments or be formed in situ. Commercially available fibreshave diameters ranging from less than about 0.001 mm to more than about0.2 mm and they come in several different forms: short fibres (known asstaple, or chopped), continuous single fibres (filaments ormonofilaments), untwisted bundles of continuous filaments (tow), andtwisted bundles of continuous filaments (yarn). Non-woven fabrics can beformed by many processes such as melt blowing, spun bonding, solventspinning, electro spinning, and carding. The basis weight of non-wovenfabrics is usually expressed in grams per square meter (gsm).

“Pant”, “training pant”, “closed diapers”, “prefastened diapers”,“pull-on diapers” and “diaper-pants” and the like as used herein areused interchangeably and refer to absorbent articles which are typicallyapplied to the wearer by first leading the feet into the respective legopenings and subsequently pulling the pants from the feet to waist areaover the hips and buttocks of the wearer and which are capable of beingpulled up or down over the hips of the wearer. Typically, such articlesmay include a front waist portion and a back waist portion which may beconnected about the hips of the wearer by integral or releasablemembers. A pant may be preformed by any suitable technique including,but not limited to, joining together portions of the article usingrefastenable and/or non-refastenable bonds (e.g., seam, weld, adhesive,cohesive bond, fastener, etc.). A pant may be preformed anywhere alongthe circumference of the article (e.g., side fastened, front waistfastened).

“Polymer” as used herein refers to but is not limited to, homopolymers,copolymers, such as for example, block, graft, random and alternatingcopolymers, terpolymers, etc. and blends and modifications thereof.Unless otherwise specifically limited, the term “polymer” includes allpossible spatial configurations of the molecule and include, but are notlimited to isotactic, syndiotactic and random symmetries.

“Rear” as used herein refers to the portion of an absorbent article orpart thereof that is intended to be positioned proximate the back of thewearer.

“Resin” as used herein refers to a solid or semisolid polymericmaterial.

“Substantially cellulose free” as used herein refers to an absorbentarticle, structure or core, that contains less than 40% by weightcellulosic fibres, less than 20% cellulosic fibres, less than 5%cellulosic fibres, no cellulosic fibres, or no more than an immaterialamount of cellulosic fibres which do not materially affect the thinness,flexibility or absorbency thereof. This definition also encompassesfully cellulose free whereby the percentage is 0%.

“Thermobonding” as used herein refers to a method of bonding fibres bythe use of heat and/or high-pressure.

“Thermoplastic” as used herein refers to polymeric materials that have amelting temperature and can flow or be formed into desired shapes on theapplication of heat at or below the melting point.

“Ultrasonic” as used herein refers to the use of high frequency sound togenerate localised heat through vibration thereby causing fibres to bondto one another.

“Water-absorbing”, “liquid-absorbing”, “absorbent”, “absorbing” and thelike as used herein are used interchangeably and refer to compounds,materials, products that absorb at least water, but typically also otheraqueous fluids and typically other parts of bodily exudates such as atleast urine or blood.

“Wearer facing layer” as used herein refers to elements of the chassisthat form the inner surface of the absorbent article, such as thetopsheet, the leg cuffs, and the side panels, etc., when such elementsare present.

“Weaving” as used herein refers to the process of interlacing two ormore sets of yarns at right angles to form a fabric; a web of fibresproduced by weaving is herein referred to as a “Woven”.

“Web material” as used herein refers to an essentially endless materialin one direction, i.e. the longitudinal extension or the length, or thex- direction in Cartesian coordinates relative to the web material.Included in this term is an essentially unlimited sequence of pieces cutor otherwise separated from an essentially endless material. Often,though not necessarily, the web materials will have a thicknessdimension (i.e. the z-direction) which is significantly smaller than thelongitudinal extension (i.e. in x-direction). Typically, the width ofweb materials (the y-direction) will be significantly larger than thethickness, but less than the length. Often, though not necessarily, thethickness and the width of such materials is essentially constant alongthe length of the web. Without intending any limitation, such webmaterials may be cellulosic fibre materials, tissues, woven or non-wovenmaterials and the like. Typically, though not necessarily, web materialsare supplied in roll form, or on spools, or in a folded state in boxes.The individual deliveries may then be spliced together to form theessentially endless structure.

A web material may be composed of several web materials, such asmultilayer non-woven, coated tissues, non woven / film laminates. Webmaterials may comprise other materials, such as added binding material,particles, hydrophilizing agents and the like.

“Wet burst strength” is a measure of a layer's ability to absorb energy,when wet and subjected to deformation normal to the plane of the web.

“Wet strength” as used herein refers to the strength of an adhesivejoint determined immediately after removal from a liquid in which it hasbeen immersed under specified conditions of time, temperature andpressure. The term is commonly used in the art to designate strengthafter immersion in water.

“Wet laying” as used herein refers to the forming a web from an aqueousdispersion of fibres by applying modified paper making techniques; a webof fibres produced by wetlaying is herein referred to as a “wetlaid”.

“Wood pulp” as used herein refers to cellulosic fibres used to makeviscose rayon, paper and the absorbent cores of products such asfeminine hygiene garments, baby diapers and pants and adult incontinencegarments.

“X-y dimension” as used herein refers to the plane orthogonal to thethickness of the article, structure or element. The x- and y-dimensionscorrespond generally to the width and length, respectively, of thearticle, structure or element.

“Z-dimension” as used herein refers to the dimension orthogonal to thelength and width of the article, structure or element. The z-dimensioncorresponds generally to the thickness of the article, structure orelement

The recitation of numerical ranges by endpoints includes all numbers andfractions subsumed within that range, as well as the recited endpoints.Unless otherwise defined, all terms used in disclosing the invention,including technical and scientific terms, have the meaning as commonlyunderstood by one of ordinary skill in the art to which this inventionbelongs. By means of further guidance, term definitions are included tobetter appreciate the teaching of the present invention.

It will be apparent to one of ordinary skill in the art that the methodand apparatus according to the present invention may be used to obtaincomposite structures, absorbent structures which may be used inabsorbent articles, and more particularly, in disposable absorbentarticles, such as feminine hygiene garments, baby diapers and pants andadult incontinence garments. Accordingly, the present invention shallnot be limited to the method, apparatus, absorbent structures andabsorbent articles specifically described and illustrated herein,although the following description is particularly directed tomanufacture of composite structures and absorbent structure forabsorbent disposable baby diaper products.

The present invention was based upon the findings that productsresulting from a method and apparatus to create a composite structurecomprising particulate material deposited in a pre-designed andcontrolled patterns, can be more efficiently used to absorb, distributeand retain liquid. Absorbent articles, such as feminine hygienegarments, baby diapers and pants and adult incontinence garments absorb,distribute, transport and contain bodily exudates. They also areintended to prevent bodily exudates from leaking, soiling, wetting orotherwise contaminating clothing or other articles, such as bedding,that come in contact with the wearer. A disposable absorbent article,such as a disposable diaper, may be worn for several hours in a drystate or in bodily exudates loaded state. Accordingly, efforts have beenmade toward improving the fit and comfort of the absorbent article tothe wearer, both when the article is dry and when the article is fullyor partially loaded with body exudates, while maintaining or enhancingthe absorbing and containing functions of the article.

Some absorbent articles, like diapers, contain a particulate material,such as an absorbent polymer material, more preferably an absorbentparticulate polymer material. Although such absorbent particulatematerial absorbs liquid and swells, it is more effective when disposedin an absorbent structure in a certain pattern or arrangement whenintending optimal absorbency, fit and/or comfort. Since it is desirablefor absorbent particulate material to remain in its intended location inan absorbent article, such particulate materials are to be clustered andare desirably relatively immobilized in the absorbent article such thatthe absorbent particulate material remains immobilized, bonded, joinedand/or restrained on their intended location when the absorbent articleis dry, partially wetted and/or fully wetted.

In addition to being absorbent, absorbent articles, such as diapers, aredesirably thin, flexible and/or light-weight, for ease and comfort inuse and for more convenient and neat packaging and storage. Absorbentarticles, which may often be used in large quantities, may alsodesirably be inexpensive. Some technologies of clustering andimmobilizing absorbent particulate polymer material in an absorbentarticle such as additional fluff, add bulk to the absorbent article andthereby increase thickness, reduce flexibility, and/or increase cost ofthe absorbent article. Other technologies for immobilizing absorbentparticulate polymer material in an absorbent article may not be aseffective in maintaining immobilization when the absorbent article is inthe wet state as when in the dry state. Accordingly, there remains aneed for a method and apparatus which can dose the absorbent particulatematerial in specified quantities, deposit, position and pocket it in adesired pattern so that thin, flexible, and/or inexpensive absorbentarticle can be obtained.

There are many technologies for attaching two functional and/orstructural layers, components, elements and/or materials together. Someof them incorporate the use of heat and/or pressure sensitive adhesivessuch as for instance hot-melts, cold-melts, heat activated adhesives,thermoplastic materials, chemical activated adhesives/solvents, curablematerials and the like, where the adhesives create the attachmentsbetween the respective materials, others involve thermo-mechanicalmethods such as for instance heat-sealing, pressure-sealing orultrasonic sealing processes where energy transfer partially links,melts or fuses multiple materials to and into each other. Correctlyapplying these methods and processes is increasingly more difficult,inefficient and/or ineffective at higher production speed in thepresence of particulate materials, for such particulate materials canoccasionally or unwillingly get in between the pocketing materials to beattached, distort the attachment process and/or reduce the strength andquality of these attachments and/or the quantity of the functionalattachments. This is specifically the case if the intermediate materialis of a flowable, fibrous or granular nature. A small particle or fiberor a lightweight flat layer can easily, due to manufacturing processfluctuations, migrate within the article or structure around thoseelements which are still substantially unattached. If intermediatematerial -even partially- ends up in the attachment area, it can or mayreduce the effectiveness, efficiency and/or strength of said attachmentor attachment method. This can be by reducing the attachment surface, byimpeding an efficient energy transfer, by creating undesirable chemicalreactions or physical effects and the like. A reduced attachmentstrength or integrity may also be due to a weaker internal strength ofthe particulate material which would then act as weakest link within thestructure and/or due to the abrasive nature of the particulate materialallowing easier rupture and/or tearing and/or loss of strength of theattachments between the respective other materials. It may also lead toa higher consumption of the particulate materials and/or other rawmaterials and thus lead to a loss of efficiency and increase in materialand/or energy cost. Another adverse effect might also be the fact thatit would cause the production processes to run slower to ensureprescribed bond formation, thus again leading to process inefficiencyand increase production costs. In a preferred embodiment of thisinvention an improved attachment method is provided which overcomes theproblems mentioned above which is specifically advantageous tomanufacture the substantially cellulose free absorbent structures havinginternal fluid management and external liquid management.

The preferred embodiment according to the present invention has resultedfrom a realization that an attachment between a carrier material and anauxiliary material in the presence of an particulate material can bemade more efficiently and effectively if the attachment area where bothmaterials are to be joined is made substantially or at least partiallyfree from said particulate material. There are various ways ofpreventing or at least minimizing the particulate material frommigrating or moving to the attachment areas in between the carrier layerand the auxiliary layer during the attachment process. If thecharacteristics of the particulate material would allow, one could forinstance use electromagnetic or electro-static forces to pull theintermediate absorbent material away from the attachment area. Alsogravitational forces can be used to allow the particulate materials to‘fall away’ from the attachment areas at the moment of attachment by wayof for instance creating respective higher and lower regions supportingthe flow of intermediate absorbent materials in between these regions.Also several purely mechanical ways of cleaning the attachment area bymeans of friction, scraping or pushing actions such as for instancebrushes, scrapers or plungers can be used. However, for some high-speedand minute applications, a still more convenient process is required.After thorough research and testing, the inventor has discovered that avery efficient way to solve the problem is by way of working withairflows. These airflows operate to evacuate the intermediate materialaway from the attachment area by blowing and/or sucking actions.

An attachment process according to a preferred embodiment of the presentinvention comprises an airflow generated by blowing zones having anoverpressure in comparison to standard process pressure or by suctionzones having an underpressure in comparison to standard processpressure. Alternatively, a combination of blowing and/or suction holescan be used to generate such airflow. An airflow moves from a zone ofhigher pressure towards a zone of lower pressure. For the sake ofsimplicity, one will use the common and easily understandable wordings‘blowing’ and ‘sucking’ although it should be understood that both areessentially the same as they create the same pressure difference. Unlessspecifically stated, an airflow from point A to B caused by a blowingzone A with a higher pressure than standard process pressure will beequivalent and can be replaced by an airflow generated by a suction zoneB with a lower pressure than standard process pressure.

Generally speaking as soon as the attachment area is made at leastpartially free from the particulate material, the attachment can be madeaccording to the conventional attachment techniques know in the art suchas but not limited to heat and/or pressure sensitive adhesives such ashot-melts, cold-melts, heat activated adhesives, thermoplasticmaterials, chemical activated adhesives/solvents, curable materials andthe like, where the adhesives create the bond between both materials,others involve thermo-mechanical methods such as heat-sealing processesor ultrasonic sealing processes where energy transfer partially meltsboth materials into each other. Preferably such fusing processes areused as opposed to attachment media.

In order not to complicate the description of the invention but withoutlimiting its scope, one will describe as if the medium in which theprocess works is a gas e.g. like the air in a normal working environmentin a manufacturing plant, and that the standard process pressure isatmospheric pressure. However, it is obvious that the invention can beused within any type of fluid, also when the medium is a liquid. So forthe description of this invention, the term ‘airflow’ will be used asbeing synonymous for a flow of fluid, meaning both a flow of gas, aswell as a flow of liquid. It is also obvious that standard processpressure should not necessarily be atmospheric pressure and thatoverpressure and under pressure will then just denominate a pressurehigher or respectively lower than the reference process pressure.

With reference to FIGS. 1A-D, 2 and 3, an absorbent structure 14 isillustrated made by a method and apparatus according to the inventionincludes at least one carrier layer 101 and at least one auxiliary layer102 and absorbent material 110. The carrier layer 101 and auxiliarylayer 102 are joined via secondary attachments 115 and preferably alsovia primary attachments 111. Apart from the primary attachments 111 andsecondary attachments 115, there are also unattached regions 119, wherethere is substantially no attachment, bond and/or joint between thecarrier layer 101 and auxiliary layer 102, thereby providing pockets 130in which the absorbent material 110 can be located to form well-designedclusters. The primary attachments 111 correspond with a primaryattachment grid, whereas the secondary attachments 115 correspond with asecondary attachment pattern. As the secondary attachment pattern willrelease under the swelling force of the absorbent materials and/or underthe influence of water, the secondary attachment 115 should have arelative low separation force is use. The primary attachment grids willpreferably be kept substantially intact.

As carrier layer 101 and/or auxiliary layer 102, having a typical basisweight in the range of 3-400 gsm, one can choose from a variety ofmaterials such as but not limited to high-lofts, airlaids, rigid,stretchable or elastic non-wovens or a woven fabric, wetlaid materialsuch as cellulose tissue, paper, film, tissue, perforated films, foammaterial, thermoplastic material, layers of adhesive or whatevermaterial suitable within the absorbent structure 14. The sandwich layerscan be made out of the same or different materials having differentcompositions, weights and/or structures. In a preferred embodiment, atleast one of the layers is liquid permeable over at least part of itssurface so that liquids can be taken up in the Z-direction. In analternative embodiment of the present invention the absorbent structure14 comprises an additional distribution layer which helps toadditionally absorb, distribute and transport liquids and having acapability to disperse the liquid permeating within said distributionlayer from the less absorbent area's (e.g. saturated) to the moreabsorbent area's (e.g. unsaturated). In yet another alternativeembodiment of the present invention the absorbent structure 14 comprisesan additional liquid-impermeable, either hydrophilic or hydrophobic,wicking layer which helps to wick, distribute and transport liquids andhaving a capability to disperse the liquid over the surface of saidwicking layer from the less absorbent area's (e.g. saturated) to themore absorbent area's (e.g. unsaturated).

Referring to FIG. 1B, the carrier layer 101 is covered on one side bydiscrete amounts of absorbent material 110, which is covered by anauxiliary layer 102. The auxiliary layer 102 lies on top of theabsorbent material 110 and is joined to the carrier layer 101 therebyproviding pockets 130 holding the absorbent material 110. Referring toFIG. 1C, it has been found that absorbent structures 14 can be formed bycombining two layers of absorbent material 110. The absorbent structure14 comprises one carrier layer 101, two layers of absorbent material 110and two auxiliary layers 102. Referring to FIG. 1D, the combinedabsorbent structure 14 as shown comprises two layers of absorbentmaterial 110, two carrier layers 101, and two auxiliary layers 102. Whentwo storage layers are joined, this is preferably done such that thefirst carrier layer 101 of the first storage layer faces the auxiliarylayer 102 of the second storage layer, while the auxiliary layer 102from upper storage layer is situated on the wearer facing surface andthe carrier layer 102 from lower storage layer is situated on thegarment facing surface of the sandwiched composite.

As can be seen from FIGS. 3 and 5, the absorbent material pattern formedin between attachments can be random or regular, substantiallycontinuously connected or isolated, fully-covering or partially coveringand/or any other suitable combination. Preferably the absorbent materialregions consists of several clusters of absorbent material 110,surrounded by areas where substantially no absorbent material 110 ispresent, which can act as additional distribution and transport channelsfacilitating the flow of liquid away from the point of insult andtowards available clusters of absorbent material 110. Weightdistribution of absorbent material 110 over the absorbent structure 14can be regular across the major surface or can profiled, i.e. the basisweight of the absorbent material 110 may change depending on itsposition in the absorbent structure 14, for instance very desirable foruse in diaper and pants cores where one would like to concentrateabsolute and/or relative more absorbent material 110 near the point ofliquid insult. Suitable materials such as for instance highly permeableSAP are offered by Evonik, BASF and Nippon Shokubai. Although preferablythe absorbent polymer material form up to 100% of the absorbent material110 it can also be used in combination with other materials such as forinstance cellulose fibres or fluff pulp, however preferably the amountof fibrous materials would not make up more than about zero to 40 weightpercent. Fully cellulose free structures benefit maximally from thisinvention.

Typical examples of methods used to join material and layers to eachother are by way of example, but are not limited to, the use of anadhesive such as for instance pressure sensitive adhesive, curing,chemical links such as for instance hydrogen and covalent bonds or viathe use of ultrasonic and/or other thermal, mechanical orthermo-mechanical attachment techniques such as for instance heatsealing, needling, air, entanglement, resistance and water jet pressure,and the like.

It is also preferred to design the attachments so that they have anaverage surface size of at least about 0.5 mm², preferably at leastabout 1.0 mm², 2 mm² or 3 mm², more preferably at least about 16 mm².Also the density of the attachments can vary, depending on the surfacesize of the individual attachments and desired separation forces. Forattachments with a surface area smaller than 1 cm² for instance, it isrecommended to use a density of at least about 100 per m². In anotherembodiment of this invention, the primary attachments 111 are arrangedin a primary attachment grid composed of continuous lines so as to allowfor additional liquid distribution and transport, for a high separationforce and high resistance against the propagation of an eventual cracksor fissures in the pockets 130. The primary attachment pattern iscarefully designed so that in a wetted state, the swollen materialremains stabilized around the locations where it was restrained and/orimmobilized in dry state. Failure to do so would result in breaking-upand/or displacement of the wet absorbent material, resulting indefective fluid management and to loss of performance, reduced fit andcomfort, even full failure. The primary attachment pattern alsoaccommodates the liquid management surface structures. The breaking ofthe secondary attachments 115 allows the carrier layer 101 and/orauxiliary layer 102 to deform, stretch and change shape. As a result,the minimal volume pockets are able to expand to an intermediate volumesand finally to maximum volume compartments so as to accommodate theextra volume resulting from the highly expandable absorbent material110. Thus, an absorbent structure 14 with expandable pockets withadditional activated free swell volume is created, allowing theabsorbent material 110 to be more effectively and efficiently used andreducing the risk of bursting of one or more sandwiching layers. Theextra volume created by the expanding pockets can for instance be about1% to 5% of the original volume. Preferably it is higher than about 5%to 25%, more preferably higher than about 25% to 50%, most preferablyhigher than about 50% or 100% of the original volume. In an alternativeembodiment, the absorbent structure 14 consists of multilayered sandwichstructures where on the first sandwich structures, whereby theadditional layers of absorbent material and/or complementary layersprovide further liquid absorption performance whilst retaining goodproduct integrity, both in a dry and wet state.

In an absorbent structure made by an embodiment of the inventionsecondary attachment 115 consist of weaker secondary attachments andstronger secondary attachments where weaker secondary attachments loosenfaster than the stronger secondary attachments. The differentfunctionalities in between the primary attachments 111 and secondaryattachments 115 in combination with the bonding strength differentiationin between weaker secondary attachments and stronger secondaryattachments allows the design of an absorbent structure 14 with apredetermined, controlled and/or phased volume-expansion of theabsorbent structure for ultimate fluid management.

With reference to FIG. 6, the present invention provides a method andapparatus for forming a composite structure 700 having a plurality ofdiscrete particulate material clusters which are preferably deposited ona carrier layer 401 and contain selected quantities of particulatematerial 201. The representatively shown apparatus includes a clusteringmeans 250 with perforations 304, and a particulate material supplyingmeans 200 for providing particulate materials 201 towards the clusteringmeans 250. A web supplying means 400 provides a carrier material 401 anda support means 600 moves the carrier material 401 adjacent theclustering means 250, the clustering means 250 preferably provided inthe form of a substantially endless rotating drum 100.

The clustering means 250 includes a pattern of perforations 304,preferably in the form inlet regions 304 a joined to outlet regions 304b, and are arranged to form and provide a desired printing pattern 320of particulate material clusters 703 onto the carrier layer 401. Thesupport means 600 is preferably in substantial contact with the supportsurface 412 of the carrier material 401. The support means 600preferably ensures a close enough connection in between the depositsurface 411 of the carrier material 401 and the outlets regions 304 b toprevent unwanted migration of the particulate materials 201 from thecarrier deposit zones 415 to the carrier inter-deposit zones 416.Although not required to work the current invention, it is highlyrecommended to foresee a close pressure contact connection in betweenthe deposit surface 411 of the carrier material 401 and the outletsregions 304 b and inter-outlet zones 309 of the clustering means 250 toprevent unwanted migration and/or shifting of the particulate materials201 from the carrier deposit zones 415 towards the carrier inter-depositzones 416. The close deposit contact ensures favourable deposit andprinting of particulate material 201 onto the deposit surface 411 of thecarrier layer 401 without substantially loss of material.

The resultant printing pattern 320 forms desired and substantiallyspaced-apart particulate material clusters 703, preferable without anysubstantial amounts of particulate materials 201 in between theparticulate material clusters 703. Preferably an additional positioningstep is foreseen by way of a providing position means, to stabilize,position and/or reposition the particulate material clusters 703 intheir exact positioning or pocketing pattern 420 before immobilising itin the composite structure. The depositing or printing pattern 320provided by the clustering means 250 can but does not necessarily haveto correspond with the positioning or pocketing pattern 420 formed bythe positioning means. For instance relative homogenous, wide or blurrydepositing patterns 320 will preferably not correspond with thediscretely clustered positioning patterns 420 required in caseparticulate material such as absorbent particulate polymer material isto pocketed and immobilised by means of primary and/or secondaryattachments made by means of ultrasonic bonding to make substantiallycellulose free absorbent structure for use in an absorbent article suchas a baby diaper or pants.

A covering means 500 provides an auxiliary material 501, such as forinstance a liquid-permeable fibrous web such as a non-woven, paper,tissue, woven, fabric, web, perforated film or foil and the like tosandwich said particulate material clusters 703, preferably comprisinglarge amounts of absorbent polymer material, between the carriermaterial 401 and auxiliary material 501. Alternatively, not preferablyhowever, the auxiliary material 501 can also represent a homogenousand/or heterogeneous layer of glue, adhesive, binders, resins,thermoplastic material and the like, capable of sandwiching theparticulate materials clusters 703 between the carrier material 401 andauxiliary layer 402. This relative expensive, technically challengingand environmentally burdensome alternative embodiment according to theinvention is not preferred above the typical non-woven, paper or tissuelayers for instance.

The clustering means 250 is suitably constructed and arranged to directa selected flow of particulate material 201 onto the carrier depositzones 415 of the carrier layer 401. It should be appreciated that otherparticulate material 201 may also be introduced via the clustering means250 as desired. A particulate supplying means 200, such as for instancea K-Tron weight and loss feeder, Model N° K10s, type of particulatedelivery system can be configured to deliver required amounts ofparticulate material 201 through a feeding tube 205 into the clusteringmeans 250. The particulate material 201 reach the perforations 304 bymeans of gravity and/or other physical forces. In particularembodiments, a conventional air-conveying system may be employed to moveand guide the particulate material 201 and resultant particulatematerial stream to the desired locations in the clustering means 250.Alternatively such forces may for instance be electro-magnetic orelectro-static forces in case the particulate material 201 is responsiveto a magnetic field or electro-charges, and magnets or charging devicesare placed to guide the particles towards the perforations 304.Alternatively, the particulate material 201 can, for instance, begravimetric or volumetric assessed, guided and fed indirectly via thefeeding tube 205 and/or directly into the clustering means 250 under theinfluence of gravity without the use of additional conveying air.

Optionally, one can also provide a vacuum suction system in function ofthe deposit zones 415 of the carrier material 401, creating an air flowtowards the perforations 304 and/or deposit zones 415. Such vacuumsuction system would generate suitable levels of vacuum within anappointed vacuum section, and would provide a desired level of vacuumwithin the clustering means 250. It should be readily appreciated thatsuch particular levels of vacuum generated within clustering means 250and/or drum 100 would depend upon the individual circumstances of themanufacturing line. For example, at higher rates of rotation of the drum100, relatively higher levels of vacuum may be required withinclustering means 250. In addition, the use of conveying means totransport the particulate material 201 into the clustering means 250 maynecessitate the use of even higher levels of vacuum. It should also bereadily appreciated that the levels of vacuum shall also depend upon theporosity of the carrier material 401, and the usage of possible carriermaterial 401 would for instance be limited to fibrous web materialsand/or perforated films and foils. For the reason above and in lighthigh energy consumption this vacuum suction usage is an alternativeembodiment according to the invention, however not one of the mostpreferred one. The positioning means can be mounted on such vacuumsuctions systems in light of the preferred pocketing pattern 420 or canalternatively be unitary.

More economically and environmentally beneficial production processeswith lower energy usage and more freedom on the choice of carriermaterial 401 are preferred. Further to extensive testing it was howeverdemonstrated that using gravity will be sufficient for a wide range ofparticulate material 201 usages at various production speeds.

The particulate material 201 supplied via the particulate materialsupplying means 200 is preferably provided in uniform particulatematerial stream, reaching a width equal to or slightly greater than thewidth 310 of the perforation pattern 300 on the side of the inletregions 304 a. In order to improve uniformity, a vibrating supply means200 might be used. In a preferred embodiment, a feeding tube 205, with aproximal opening 206 and distal opening 207 can be used to concentratethe particle material stream onto a certain area. Such feeding tube 205may have various suitable longitudinal and transversal shapes and ispreferably designed in light of the dimension and shape of theclustering means 250, its perforation pattern 300, its perforations 304and the desired printing pattern 320. The feeding tube 205 may alsoconverge towards the clustering means 250 to effectively and efficientlyguide the particulate material stream to the inlet regions 304 a. Theparticle supply means 200 preferably contains a continuous supply and adosing system 204 of a gravimetric, volumetric or other type so as tocontrol the quantity and quality of particles fed into the perforations304. Such particle supply means are being offered by Acrison, Inc.,having offices in New Jersey, New York.

The particle material 201 such as absorbent polymer material, morepreferably absorbent particulate polymer material may be provided andused in various shapes or forms, such as granular, spherical, flakes,fibrous, and will often consist of irregularly shaped particles, havinga mean particle size from about 10 μm to 1000 μm, preferably with lessthan about 5% by weight having a particle size of 5 μm, and preferablywith less than about 5% by weight having a particle size of more thanabout 1200 μm. For use in absorbent structures to be used in absorbentarticles, an absorbent material will be selected which can swell uponcontact with liquids, such as bodily exudates. Such materials can besupplied in a granular form by Evonik from Essen, Germany, BASF fromAntwerp, Belgium, Nippon Shokubai from Osaka, Japan and San-Dia fromTokyo, Japan. These are cross-linked polymeric materials that can absorbat least about 5 times their weight of an aqueous 0.9% saline solutionas measured using the Centrifuge Retention Capacity test (Edana441.2-01).

The web supplying means 400 can include any conventional spindle andsupply roll controlling mechanism of the type that is know in the art.For example, suitable spindle and control mechanisms are available fromMartin Automatic, company with offices in Rockford, Illinois.

The carrier material 401 may preferably be brought in their desiredposition via guiding systems 402 and the auxiliary material 501 maypreferably be brought in their desired position via the guiding systems502, and the support means 600 is preferably controllably strained viatensioning means 603 and operated via guiding means 601 and 602. Thecomposite material 700 is preferably guided via guiding means 603 andthe desired material 702 is preferably guided by guiding means 604.

The carrier material 401 can be any suitable material web which hassufficient strength to process through the apparatus, and preferablyeconomically, environmentally and usage sensible. The carrier material401 may comprise a paper or fibrous tissue, woven or non-woven fabric, acellulose web or batt, airlaid or wet laid structure or the like.Alternatively, the carrier material 401 is a porous, gas permeable webmaterial such as a porous film or fibrous web.

The auxiliary material 501 can be any suitable material web which hassufficient strength to process through the apparatus, and preferablyeconomically, environmentally and usage sensible. The carrier material401 may comprise a paper or fibrous tissue, woven or non-woven fabric, acellulose web or batt, airlaid or wet laid structure or the like.Alternatively, the carrier material 401 is a porous, gas permeable webmaterial such as a porous film or fibrous web. Furthermore the auxiliarymaterial 501 can also represent for instance a spray, film and/or layerof glue, adhesive, binders, resins, thermoplastic material and the liketogether with the carrier material 401 capable of sandwiching theparticulate material clusters 703.

The carrier material 401 and/or auxiliary material 501 may also be anessentially endless web material in the longitudinal direction. Onepreferred web material is a so called SMS material, comprising aspunbonded, a melt-blown and a further spunbonded layer. Highlypreferred are permanently hydrophilic non-wovens, and in particularnonwovens with durably hydrophilic coatings. An alternative preferredmaterial comprises a SMMS-structure. Another preferred web material is anonwoven containing cellulosic fibers, paper or tissue sheet or otherairlaid, drylaid or wetlaid material, as these products greatly improvethe wicking capacity of the product. The carrier and auxiliary materials401 and 501 may be provided from two or more separate sheets ofmaterials or they may be alternatively provided from a unitary sheet ofmaterial. Preferred non-woven materials are provided from syntheticfibers, such as PE, PET and most preferably PP. As the polymers used fornon-woven production are inherently hydrophobic, they are preferablycoated with hydrophilic coatings.

The clustering means 250 can preferably be mounted onto a or unitarywith a drum 100 having perforations 304 arranged in a perforationpattern 300 along its circumferential- and/or width-wise direction andthus directly or indirectly piercing or perforating the drum 100 in theradial direction, from its inner surface 101 to its outer surface 102.Alternatively, according to another embodiment of the invention, theclustering means 250 are replaceably mounted and/or unitary incorporatedon a substantially endless belt carried on a system of transportingrollers. Suitable forming belt systems are available from PaperConverting Machine Company, a business having offices located in GreenBay, Wis. Driving means, such as conventional electric motors or thelike, are constructed and arranged to rotate or otherwise move andtranslate the clustering means 250 at a predetermined surface speedalong a desired manufacturing direction and speed. Variousconfigurations can provide the desired composite structures whileoperating at high surface speeds of at least about 0.5 m/sec, preferablyat least about 1 m/sec, more preferably at least about 3 m/sec and mostpreferably more than 7 m/sec.

The carrier material 401 is delivered onto or adjacent the outerperipheral surface of the clustering means 250 mounted onto or unitarywith drum 100. As the drum 100 rotates, the moving surface of the drum100 transports the clustering means 250 and the support means 600 guidesthe carrier material 401 in close proximity and past the clusteringmeans 250 in light of the intended deposit of particulate materialclusters onto the deposit surface 415 of the carrier layer 401. For thesake of simplicity, the wording ‘drum’ is used, denominating anessentially round circumference, but it is clear to the person skilledin the art that any type of endless body, provided with the desiredperforation pattern 300 can be used. The surface of such body can berigid such as in perforated aluminium plates, or soft such as in a belt.Preferably, a drum 100 made out of steel frame with reinforced aluminiumplates will be used.

With reference to FIG. 7, in a preferred embodiment according to theinvention the outer surface 202 of the drum 100 can be operationallydivided into a series of predetermined article segments 275. Eacharticle segment 275 mounted and incorporated into the drum 100 generallycorresponds to an absorbent structure 14 for placement in a singleabsorbent article. The outer surface 202 of the drum can furthercomprise a plurality of plate means 260 which comprise the clusteringmeans 250 and are serially positioned and longitudinally spaced alongthe circumference of the drum 100 so as to provide a series of mountableclustering means 250 able to deposit the particulate material 201 on thecarrier material 401. Preferably the article segment 275, the platemeans 260 and clustering means 250 are designed so as to complement therounded drum 100. The different sections making up the drum 100 areconstructed of a material, such as metal, that is sufficiently strong towithstand the forces and stresses encountered during operation.

The perforations 304 can have a variety of shapes including, but notlimited to, circular, oval, square, rectangular, triangular, and thelike. The perforation pattern 300 shown in FIG. 8 is a square grid withregular spacing and size of circular perforations 304. Other perforationpatterns 300 can be hexagonal, rhombic, orthorhombic, parallelogram,triangular, rectangular, and any and all combinations and derivationsthereof. Alternatively, using an irregular perforation pattern 300 withvarying sizes and shapes of the perforations 304, very specific and/orcomplex resultant printing patterns 320 can be made. The spacing betweenthe grid lines 303 may be regular or irregular. Alternatively theconfigurations of the perforation 304 can also be arranged with one ormore elongate shapes positioned with their relatively longer axesaligned at selected angles which diverge or converge to the centerlineof the perforation pattern 300. The desired perforation 304, and theirrespective inlet region 304 a and outlet region 304 b volumes, arefurthermore formed by height 305 of the individual clustering means 250.

With reference to FIG. 9, the perforation patterns 300 will determinethe depositing patterns 415, whereby the particulate materials 201 willpreferably be deposited in the carrier deposit zones 415 on the carriermaterial 401 and preferably not onto the carrier inter-deposit zones416. In a preferred embodiment the additional positioning means providesfor the (re)positioning of the depositing pattern 415 to their finalpocketing pattern 420. This is especially advantageous in case ofhomogenous or heterogeneous particulate material depositing, but is alsogreatly preferred to focus the particulate materials 201 from theirdepositing pattern 415 and from the inter-deposit zones 416 to exactpocketing pattern 420, before immobilising them by creating for instanceprimary and secondary attachments in between the carrier material 401and the auxiliary material 402.

With reference to FIG. 10, clustering means 250 includes a pattern ofperforations 304 separated from one another by inter-perforation zones,being preferably inter-inlet ridges 303 on the feeding side of theclustering means 250 and inter-outlet zones 309 on the deposit side ofthe clustering means 250. The perforations 304 have a top opening 302,corresponding to the inner surface 211 of the drum, a bottom opening301, corresponding to the outer surface 212 of the drum, and a height305. Top opening 302 and bottom opening 301 can vary in size and shapefrom each other, where the top opening 302 is in this instancerectangular with transversal side 306 and longitudinal side 307 and thebottom opening 301 is in this instance circular with diameter 308. In apreferred embodiment, the top opening 302 is larger than the bottomopening 301, thus creating a converging funnel structure in the inletregion 304 a, allowing the efficient collection of particle material 201which slides easily into the outlet region 304 b. In a preferredembodiment, the top opening 302 are designed as such that theinter-inlet ridges 303 between adjacent top openings 302 are very sharpand narrow so that substantially no particulate material 201 can remainand/or pile up on these inter-inlet ridges 303 and thus substantiallyall particulate material 201 is collected by the perforation 304.

If the perforations 304 are overfilled, i.e. if more particulatematerial 201 is present than the perforations 304 can take or than caninstantaneously be evacuated via the perforations 304, one has‘overfill’. Particulate material 201 will then accumulate and rise untilabove the level of the top opening 302 of the perforation 304. In thatcase, a sweeping means 208 will level the surface of the particulatematerial 201 with that of the inner surface 213 of the drum 100 and thusremove the excess particulate material 201 so that only a volume ofparticulate material 201 essentially corresponding to the volume of theperforation 304 is being transferred to the carrier material 401 duringdepositing. The sweeping means 208 can be for instance a scraper barmade out of durable material, or, as depicted in FIG. 6, a rotatingbrush or wheel 208 mounted closely above the inner surface 213 of thedrum 100, or any other suitable solution fit for the purpose. Suchsweeping 208 means will also evacuate any particulate material 201present on the ridges 303 between the adjacent top openings 302. If theperforations 304 are under-filled, i.e. in case the particulate materialsupply means 200 feeds less particulate material 201 (by volume) intothe perforations 304 of the clustering means 250 than can be evacuatedduring the depositing process, one has ‘under-fill’. This is preferredin application, especially where it is important to have the correctweight of particulate material 201, rather than working via the volumeof the particulate material 201.

As explained above, the overfilling method functions with sweeping meanscan act as a volumetric dosing system, where the prescribed volumes,dimensions and shapes of the perforations 304 act as the volumetricdosing and printing space and gives excellent results if the particulatematerial 201 is very homogeneous in density and particle size, or if theweight of the dosed particles is less relevant than their volume.

However, in many cases it is required to dose the correct weight, ratherthan the corresponding volume. Such particulate material 201 often haveirregular densities by nature and/or such irregular densities are oftenaggravated by handling and transportation whose vibrations cause theparticulate material 201 to segregate, bringing the lower densityparticles on top and the higher density particles below. Using avolumetric method could then result in important weight differences fromone product to another which is undesirable, making gravimetric dosingpreferably.

Carrier material 401 which is delivered by the web supplying means 400onto the support means 600 delivers the carrier material 401 in closeproximity of and preferably against the outer periphery of theclustering means 250. If the clustering means 250 and the carriermaterial 401 are pressed to one another they tightly seal off the outletregions 304 b and when preferably moving at essentially zero speeddifference to one another, the particulate materials 201 fed by thesupply means 200, preferably guided via feeding tube 250, are able to becontinuously and controllably deposited onto the clustering means 250into the perforation 304 via the inlet regions 304 a thereby creatingthe particulate material printing pattern 320 on the deposit zones 415of the carrier material 401. Preferably the printing pattern 320 istreated via positioning means so as to reposition the particulatematerials 201 into the pocketing pattern 420. Optionally, theparticulate material clusters 703 are immobilised, bond, joined and/orotherwise secured restrained in relation to the carrier layer via anysuitable means, such as for instance glue, binder, sprays, films,network, webs, etc.

Due to the gravity or other forces, the particulate material 201 willexit the perforations 304 via their bottom opening 301, therebyproviding the desired printing pattern 320. This desired printingpattern 320 is substantially retained when the drum 100 separates fromthe carrier material 401. In the absence of a relative close seal inbetween the outer surface of the clustering means 250 and the depositsurface 411 of the carrier material 401, a gap 103 will create apossible blurring effect of the desired printing pattern 320, since thedrum 100 and carrier layer 401 move at significant speeds and allowmigration of the particulate materials 201. Therefore it is recommendedto keep the gap 103 a small as technically acceptable.

However, even with a very small gap 103, it is obvious to the personskilled in the art that, depending on the nature of the particulatematerial 201 and on the amount of particulate material 201 one wants todeposit via one single perforation 304, the actual resulting printingpattern 320 might differ slightly from the perforations pattern 300. Theeffect is caused by gravity which might pull the particulate materialclusters 703 apart so that the particulate material footprint 705 on thecarrier layer 401 is wider and/or larger than the bottom opening 301 ofthe perforations 304 and the forces of inertia might further distort theprinting pattern 320 in the direction of the web movement, therebycreating a skewed image 704. The additional positioning means are usedto overcome this disadvantageous blurring effect completely and focusall particulate material 201 in their pocketing pattern 420.

FIG. 11 illustrated how, due to the various forces mentioned above, fora set of printed particulate material clusters 703, the printed shape702 might differ from the original shape 701 which the particulatematerials 201 had while still caught in the perforation 304 of theclustering means 250 before being deposited on the carrier layer 401. Acareful design of sizes, locations and shapes of the perforations 304and related dimensions, shapes and rotating speed of the clusteringmeans 250 and drum 100 will ensure satisfying results after havingevacuated the particulate material 201 onto the carrier material 401.

The composite structure 700 as a combination of the carrier material 401and the particulate material clusters 703 is moved away from saidclustering means 250 via a transport means, while in case required apositioning means ensures the particulate material clusters 703 are notunacceptably distorted, the particulate materials 201 do notunintentionally migrate to the inter-deposit zones 416 and/or are lostor wasted due for instance high machine speeds, air and material flows,gravitational and other forces and the like. In a preferred embodimentthe composite structure 700 is immediately stabilised when taken overfrom the carrier material support means 600 by the positioning meansbeing for instance opposing contact pressured longitudinal conveyerbelts, vacuum suction means, or the like. The support means 600 or othertransport means can be unitary with positioning means.

More preferably one can also immediate bond or join a second webmaterial such as for instance an auxiliary material 501 directly orindirectly unto the carrier material 401 and the particulate materialclusters 703 deposited thereon according to printing pattern 320, sothat the particulate materials 201 are sandwiched, immobilized, bonded,joined and/or restrained in between the carrier material 401 andauxiliary material 501 in their desired location and shapes by means ofthe thereby formed pockets. The auxiliary material 501 can representvarious known alternatives and techniques of immobilization, bonding,joining and/or restraining means, such as for example homogenous and/orheterogeneous patterns, shapes, lines, sprays, coatings and/or films offor instance glues, binders, resins, plastics, adhesives, curing agents,heat activated and heat sealing adhesive, pressure sensitive adhesiveand the like.

The shape of these positioning means can have a variety of shapesincluding, but not limited to, circular, oval, square, rectangular,triangular, and the like. The positioning pattern 420 of the positioningmeans is preferably a grid with regular spacing and size of circular orrectangular recessions and/or elevations. Other shapes can be hexagonal,rhombic, orthorhombic, parallelogram, triangular, rectangular, and anyand all combinations and derivations thereof. Alternatively, using anirregular positioning pattern with varying sizes and shapes, veryspecific and/or complex resultant positioning patterns can also be made.The spacing between the recessions and/or elevations may be regular orirregular. Alternatively the configurations of the positioning means canalso be arranged with one or more elongate shapes positioned with theirrelatively longer axes aligned at selected angles which diverge orconverge to the centerline of the positioning pattern 420. Thepositioning means can be unitary with the attachment means.

As shown in FIG. 6, a first adhesive applicator 900, spraying adhesiveonto the carrier material 401 prior to the deposit of the particulatematerial 201 may be provided. The auxiliary material 501 may also beprovided with a second adhesive applicator 901 and the resultingsandwich structure is additionally preferably secured via an ultrasonicattachment means 800.

The first and second adhesive applicator 900 and 901 can be constructedand/or operated so as to provide a multiplicity of overlapping loops ofswirled adhesive to hold together the composite web 700. A plurality ofadhesive swirl patterns can be selectively overlapped to provide thedesired level of bonding and/or joints within the appointed pockets. Itshould be readily appreciated that other configurations of the adhesivepatterns, such as stripes or individual islands of adhesive may beemployed to give operable bonding. In addition, it should be readilyappreciated that other types of adhesive application systems, such asprinting, spraying, extrusion, or the like, may also be employed togenerate the desired arrays of patterned adhesive. Alternatively thesecond adhesive applicator 901 can be placed directly above thecomposite structure 703 so as to directly spray upon and immobilize,bond, join and/or restrain the particulate materials clusters 703 ontothe auxiliary material 401, whereby the sprayed layer of adhesive wouldform the respective auxiliary material 501. In light of economic,environmental and technical considerations this adhesive immobilization,bonding, joining and/or restraining of the composite structure 700 ishowever not preferred and only considered an alternative embodimentaccording to the invention. The adhesive applicators 900 and 901 can besupplied by Nordson, United States, whereas a adhesives can be suppliedby Henkel, Germany.

Alternatively the auxiliary material 501 can for instance also comprisea liquid-permeable layer or web material, such as films, foils, tissues,fabrics, webs or the like. The layer may for instance comprise paper,tissue, wetlaids or drylaids, wovens or non-woven and/or may be composedof for instance hydrophilic materials or composed of a hydrophobicmaterial which has been suitably treated to render it sufficientlyhydrophilic. An alternative configuration of the auxiliary material 501can, for example, comprise a cellulosic layer of fluff or wood pulp. Thefluff or wood pulp layer may be substantially unbonded, or optionallyand preferably provided with the necessary structural and/or functionalintegrity by the means know in the art (e.g. air jet, water jet,knitting, calendaring, sonic bonding etc.) and/or may include a selectedproportion of a bonding agent, such as a resin, adhesive, thermallyfusible fiber or the like, which is operably distributed therein. Forexample, a thermally fusible, thermo-bonding fiber composed of apolyethylene/polypropylene, sheath/core bi-component fiber may also beemployed.

Additionally the composite structure 700 and/or absorbent structure 14can be alternatively and/or complementary be further combined with anyand all other suitable covering, absorbency feature enhancing,protective, functional, structural and/or strengthening materials,fabrics and/or webs (e.g. acquisition layer, surge layer, distributionlayer, wicking layer, backing layer, elastic layer, colored layer,perfumed layer, lotion layer, informative layer, etc.) etc.

Auxiliary material 501 can preferably be bound or joined to the carriermaterial 401 with the particulate material clusters 703 immobilizedand/or restrained there between via attachment means 800 such as forinstance ultra sonic and/or other thermal, mechanical orthermo-mechanical bonding techniques. Such discrete bonds or joints inbetween the carrier material 401, particulate material clusters 703and/or auxiliary material 501 can preferably be provided in one or moreof the inter-deposit zones 416, more preferably in one of theinter-positioning zones, in the form of grids, patterns, lines, dots andthe like.

In a particular aspect of the invention, the ultrasonic attachment means800 can be configured to creating substantially permanent primaryattachments 111 and substantially detachable or temporary secondaryattachments 115 as show in the absorbent structure illustrated inFIG. 1. The attachment means provide an attachment and detachment systemwherein the strength of the attachment means is great enough toadequately hold the carrier material 401 and the auxiliary material 501together when the system is substantially dry and also when theabsorbent structure is partially or fully wetted. In addition theattachment and detachment system is configured to be sufficiently low soas to not excessively constrict the swelling expansion of absorbentparticulate polymer materials during the absorption of liquid. Thestrength of the attachment means is preferably less than the separatingforce imparted by the swelling of the high absorbency material when theabsorbent particulate polymer material is exposed to liquids. Inaddition, the attachment system is preferably configured to release atan applied load which is less than the load needed to delaminate theattachment means without excessively tearing the material forming eitheror both of the carrier material 401 and/or auxiliary material 501 whensuch layers are wetted. The attachment system is preferably alsoconfigured to release at an applied load which is less than the loadneeded for the wetted absorbent material to burst through the materialforming the absorbent structure. Typically, the applied load is agenerally tensile load resulting from the pressure exerted by theexpanding absorbent particulate polymer material when the particulatematerial absorbs liquid and swells. The appropriate attachment means areconstructed and arranged to be sufficiently strong to withstand thispressure and substantially avoid bursting or tearing. Most preferablyultrasonic bonding systems are used to manufacture such compositestructures which can for instance be supplied by Herrmann, from Germany.

The attachment means for securing together carrier material 401 andauxiliary material 501 may also be constructed to provide any othersuitable connecting mechanism, such as adhesive bonds, thermal bonds,sonic bonds, stapling, stitching, or the like. The attachment means 800can preferably be configured to provide operable pockets particulatematerial clusters 703 between the carrier layer 401 and auxiliary layer501. Optionally, a perimeter means can be included in the process toobtain a mechanism for providing substantially continuous sideattachment regions, and a selected pattern of intermittent,longitudinally-spaced, medial attachment regions. Suitable applicatordevices are available from Nordson, a business having offices located atNorcross, Ga. Where the perimeter attachment means preferably comprisesan adhesive applicator, the applicator may also be configured to applythe adhesive by employing various conventional techniques, such asprinting, extrusion, spraying, or the like. In alternativeconfigurations, the perimeter attaching means may be configured toprovide other types of securing, such as sonic bonds, thermal bonds,stitching, sewing, etc.

The auxiliary material 501 can preferably be provided by covering means500 and a guiding system 502 of transporting rollers and conveyers whichare configured to deliver the auxiliary material 501 into a contactingrelation with the composite structure 700 comprising a carrier material401 and the printing pattern 320 of particulate material clusters 703.

With reference to FIG. 13, a preferred embodiment of an apparatus andmethod according to this invention is illustrated, particularly suitablefor manufacturing at very high speed super absorbent particle sheets asabsorbent structures for absorbent articles such as a baby diaper.

It includes a particle supply means 200 with feeding tube 205, recoverytube 215 and deflector 220, a clustering means 250 in the form of anessentially endless rotating drum 100, comprising perforations 304 in adesired perforation pattern 300. Below and in close proximity to therotating drum 100, a moving carrier layer 401 is arranged onto anessentially endless support means 600, preferably moving at essentiallythe same speed as the rotating drum 100. Particles 201 falling out ofthe feeder means 200 in the drum 100 and onto the clustering means 250into the perforations 304, thereby catching and gathering the desiredamount of particulate material 201 for building up the particulatematerial clusters 703 which are to be deposited according to printingpattern 320. Via a takeover drum 650, with suction segment 651, thecomposite structure 700 of carrier layer 401 with printed pattern 320 isremoved form the clustering means 250 and drum 100 before being coveredby an auxiliary layer 501. A stripper roll can also be employed to helpseparate the composite structure 700 from the drum 100. An ultrasonicattachment system 800 is provided to bond and/or join the various layersof material to one another and preferably creating the predefinedpockets with the particulate material clusters 703 by way of providingpermanent and/or detachable bonds and/or joints within the inter-depositzones 416 or inter-position zones, preferably throughout the absorbentpolymer particulate material area. The positioning means, herein unitarywith 651, stabilises, positions and/or repositions the particulatematerial 201 into its pocketing position 420 until it has beensandwiched and fixed by the ultrasonic sealing, creating the desiredmaterial 702. The takeover drum 650 preferably functions also as anvilfor the ultrasonic tool. After the assembling operation has formed thedesired material 702, the absorbent structure is preferably directed toother areas of the apparatus for further processing.

Creating constantly and quickly repeating pulses of particulate material201 suspended in a conveyer means 225 such as air has been a longlasting desire for many applications, in particular for pulses which arewell controlled both with regard to their shape, their frequency and theamount of material transferred during these pulses. A particular usefulapplication is during the manufacture of disposable absorbent articles,such as feminine hygiene garments, baby diapers, baby pants and/or adultincontinence garments and the like, where the manufacturing aims at highproduction speed and low variability. This can be achieved by means ofthe deflector 220 which will interrupt the particle material stream bypushing the particulate material 201 into a recovery tube 215 and canthus create pulses of particulate material 201. The advantage is thatone can thus choose not to print certain segments of the drum 100, i.e.leave certain areas of the perforation pattern 300 void of particlematerial. Also, the unprinted segments of the drum 100 can vary from onerotation of the drum to another, thereby saving enormously on theinvestment cost of providing different drums 100 with differentperforation pattern 300, and on the maintenance and production cost ofchanging such different drums 100. As an example: with this solution, itis possible to manufacture composite structure 700 or absorbent for theuse in absorbent articles such as diapers in all sizes, from thesmallest one to fit a newborn baby unto the bigger ones for toddlers, onjust one drum 100, which is not possible with conventional techniquesknown in the art and is highly appreciated and advantages.

FIG. 12 provides schematic enlarged sectional view of a part of theclustering means 250 depositing particulate material 201 via theperforations 304 onto their deposit region 415 according to a printingpattern 320 according to the process shown in FIG. 13. The perforations304 are shown in four exemplary and non-limitative different statesduring the method according to the present invention; the first state“A” being the empty phase, just before loading of the perforations 304or after having fully evacuated particulate material 201 there from; thesecond state “B” being the fully loaded state whereby the perforations304 have collected particulate materials 201 so as to fill theperforation 304; the third state “C” being the start of the depositingprocess (partially) whereby the carrier layer 401 and the outer surfaceof the clustering means 250 are gradually moving away from each othersuch as is for instance the case when the substantially endless rotatingdrum 100 is departing from the carrier layer 401 thereby allowingpartial evacuation of the particulate material 201; the last state “D”being the essentially full deposit of the particulate material cluster703 onto the carrier layer 401 so as to, after full evacuation of theparticulate material 201 onto the carrier layer 401, to return back tostate “A”, again allowing catching and collection of particulatematerials 201 filling the void space for another particulate materialcluster 703 depositing and printing pattern 320 process.

With reference to FIG. 14, a carrier material 401 and an auxiliarymaterial 402 will be attached in an attachment area 2, in the presenceof an intermediate absorbent material 110. An attachment means 90 suchas an adhesive is provided. A blowing hole 40 provides a blowing flow41, creating resulting flows 60 which help to evacuate the intermediateabsorbent material 110 from the attachment area 2. The carrier material401 can be more or less air permeable. If the carrier material 401 hashigh air permeability, the airflow will more easily pass through thematerial and have a direct impact on the intermediate absorbent material110 which will be evacuated more easily. In order to fully optimise theblowing flow 41, it is preferable though not necessary that theauxiliary material 402 is less or not air permeable. If the auxiliarymaterial 402 is air permeable, it is possible to place and an additionalmaterial or mask 70 on top of the auxiliary material 402 so as to reduceor prevent air passing through the auxiliary material 402. The presenceof an attachment means 90 such as a layer of adhesive will also form anextra barrier against air passing through the auxiliary material 402.With reference to FIG. 15, a carrier material 401 with lower airpermeability has been used. Here the blowing flow 41 will result in aforce directed upon the carrier material 401, relocating and liftingthis carrier material 401 and thereby indirectly evacuating theintermediate absorbent material 110 from the attachment area 2. In mostcommon materials, a combination of both effects, with some air passingthrough the carrier material 401 and directly evacuating theintermediate absorbent material 110, and some air remaining underneaththe carrier material 401 and lifting this, will occur. With reference toFIG. 16, an auxiliary material 402 and a carrier material 401 will beattached in an attachment area 2, in the presence of an intermediateabsorbent material 110. Suction holes 30 provide a suction flow 31 andblowing holes 40 provide a blowing flow 41. As a result, there is aresulting flow 60 which helps to evacuate intermediate absorbentmaterial 110 from the attachment area 2. With reference to FIG. 17, anauxiliary material 402 and a carrier material 401 will be attached in anattachment area 2, in the presence of an intermediate absorbent material110. Blowing holes 40 provide a blowing flow 41 via a blowing orifice 42which is protruding from the tool surface 3. As a result, there is aresulting flow 61 which helps to evacuate the intermediate absorbentmaterial 110 from the attachment area 2. The attachment means 90 can bea separate medium, such as for instance an adhesive (not shown).Alternatively, the protruding part 43 could act as an anvil for thesealing tool 80, which can for example be an ultrasonic hammer thuscreating an ultrasonic attachment between auxiliary material 402 andcarrier material 401. Alternatively, sealing tool 80 can be a heatsealing equipment, creating a heat sealed bond. The sealing tool 80could then at least partly fulfil the function of blocking material 70from FIG. 14. In FIG. 18, the protruding parts 43 of blowing holes 40with blowing orifices 42 touch each other to form protruding arrays 45.In the midst of these arrays 45, there are evacuating channels 46efficiently directing air flow and evacuating the intermediate materialfrom attachment area 2.

It should be noted that at least part of the intermediate absorbentmaterial 110 should be evacuated from the attachment area 2 prior to theattachment being made. This does not imply that auxiliary material 402and carrier material 401 are both present when the intermediateabsorbent material 110 is at least partly evacuated. On the contrary,one could easily provide the carrier material 401, evacuate part of theintermediate absorbent material 110 from the intended attachment area 2and then, in a subsequent step, add the auxiliary material 402 andattach it to the carrier material 401.

FIG. 19 shows another preferred embodiment of this invention. Anauxiliary material 402 and a carrier material 401 will be attached in anattachment area 2, in the presence of an intermediate absorbent material110. The top material (not shown) will be added to the structure afterat least part of the intermediate absorbent material 110 has beenevacuated from the attachment area 2. A suction hole 30 provides asuction flow 31. An additional material or mask 71, having some openingswhich are not in line with the suction hole orifice 32 is provided. Thecombination of the suction force and the openings creates resultingflows 60 which help to evacuate the intermediate absorbent material 110from the attachment area 2 by gathering it in an intermediate materiallanding zone 33.

For many applications, working with a suction segment can be moreadvantageous than working with a blowing segment as the latter oftenleads to a more turbulent airflow, resulting in less control of theevacuation of the intermediate material. However, it is clear that notall turbulence should be avoided for it can be used for the advantage ofthe process, as shown in FIG. 20. FIG. 20 shows a carrier material 401is covered with an intermediate absorbent material 110. Underneath thecarrier material 401 are suction holes with square suction holeorifices. By transporting the carrier material 401 and intermediateabsorbent material 110 underneath a perforated mask 71, secondaryairflows are created. These secondary airflows are somewhat turbulent innature and guide the intermediate absorbent material 110 away from theattachment areas 2 where the intermediate absorbent material 110 findsfew support towards the intermediate material landing zones 33 wherethere is a suction keeping it fixed.

FIG. 21 shows a process equipment for manufacturing an absorbentstructure 14 with an intermediate absorbent material 110. A carriermaterial 410 is being provided and guided onto a rotating drum 200.Intermediate absorbent material 110 of a granular nature is provided outof a particulate material supplying means 200 via a dosing system 204.Within a section segment 651 of the drum 100, an underpressure or vacuumis created via perforations with orifices 32. Above the drum, there is amask 71 with openings, creating airflows which will guide theintermediate absorbent material 110 onto the positioning pattern 420 andaway from the inter-positioning zones. An auxiliary layer 402 is addedand it is attached to the carrier material 401 20 by means of anultrasonic equipment 81 with a hammer 80. The drum 100 acts as anvil forthe ultrasonic sealing. The resulting absorbent structure 14 is guidedaway from the equipment.

The process for producing preferred absorbent structures in accordancewith the present invention comprises the following steps: A carrierlayer 10 is provided onto which absorbent intermediate material 50 isdisposed by methods known in the art. To deposit the absorbent material50, vacuum, gravity, airflow or other forces can be used. Then anauxiliary layer 20 is provided, covering the absorbent material 50, andprimary bonding regions 2 and secondary bonding regions 4 are beingprovided. In case one would like to use adhesives or chemical binders,then it might be useful to attach these to the carrier layer 10 and/orauxiliary layer 20 prior to bringing the sandwich structure together. Incase one opts for thermo-sealed bonding areas, then the thermo-sealingcan be applied after the sandwich structure components have been broughttogether. It is of course also possible to combine both techniques inthe same absorbent structure.

The sizes and shapes of the holes, the pressure differences and otherparameters described in this invention may vary and depend on theapplication. However, the person skilled in the art will be able todetermine the settings which are most suitable for his application. Forexample, for absorbent article applications in personal hygiene, such asin the manufacturing sheet with absorbent polymer materials, theabsorbent structure 14 can be manufactured according to settings asdescribed above in relation to FIGS. 20 and 21. The perforations in themask can be manufactured having a diameter between 0.5 mm and 10 mm,more preferably between 2 and 7 mm, and most preferably between 3 and 5mm. The distance to the rotating drum is preferably smaller than 25 mm,more preferably smaller than 15 mm and most preferably around 5 mm. Thevacuum or under pressure in the suction segment 651 should preferably belarger in magnitude than −1.0 kPa, more preferably larger in magnitudethan −7.5 kPa and most preferably larger in magnitude than −15 kPa. Theauxiliary and carrier materials can be chosen from a wide range ofmaterials. It has been found that using polypropylene spunbondednonwoven materials with a weight between 8 and 20 grams per sqm giveexcellent results.

FIG. 22 is a top plan view of a diaper 10 as a preferred embodiment ofan absorbent article including an absorbent structure made according tothe present invention. It should be understood, however, that thepresent invention is also applicable to other absorbent articles such asfeminine hygiene garments, baby pants, adult incontinent garments andthe like.

The absorbent article is shown in its flat out, un-contracted state withthe wearer side facing the viewer. Portions of the absorbent article arecut away to more clearly show the underlying structure of the diaper 10including the absorbent elements and absorbent components. The chassis12 of the diaper 10 in FIG. 22 comprises the main body of the diaper 10.The chassis 12 comprises an outer covering including a liquid pervioustop sheet 18 and/or a liquid impervious back sheet 20. The chassis 12may include a portion of an absorbent structure 14 encased between thetop sheet 18 and the back sheet 20. The chassis 12 may also include mostor all of the absorbent structure 14 encased between the top sheet 18and the back sheet 20. The chassis 12 preferably further includes sidepanels or ears 22, elasticized leg cuffs 24 and elastic waist features26, the leg cuffs 24 and the elastic waist feature 26 each typicallycomprise elastic members 28. One end portion of the diaper 10 isconfigured as a front waist region 30 of the diaper 10. The opposite endportion is configured as a back waist region 32 of the diaper 10. Anintermediate portion of the diaper 10 is configured as a crotch region34, which extends longitudinally between the first and second waistregions 30 and 32. The waist regions 30 and 32 may include elasticelements such that they gather about the waist of the wearer to provideimproved fit and containment (e.g. elastic waist feature 26). The crotchregion 34 is that portion of the diaper 10 which, when the diaper 10 isworn, is generally positioned between the wearer's legs. The diaper 10is depicted with its longitudinal axis 36 and its transverse axis 38.The periphery of the diaper 10 is defined by the outer edges of thediaper 10 in which the longitudinal edges 42 run generally parallel tothe longitudinal axis 36 of the diaper 10 and the end edges 44 runbetween the longitudinal edges 42 generally parallel to the transverseaxis 38 of the diaper. The chassis 12 also comprises a fastening system,which may include at least one fastening or securing member 46 and atleast one landing zone 48. The various components within the diaper 10may be bound, joined or secured by any method know in the art, forexample by adhesives in uniform continuous layers, patterned layers orarrays of separate lines, spirals or spots. The top sheet 18, the backsheet 20, the absorbent structure 14 and other components may beassembled in a variety of well-known configurations and are well knownin the art.

The back sheet 20 covers the absorbent structure 14 and preferablyextends beyond the absorbent structure 14 toward the longitudinal edges42 and end edges 44 of the diaper 10 and may be joined with the topsheet 18. The back sheet 20 prevents the bodily exudates absorbed by theabsorbent structure 14 and contained within the diaper 10 from soilingother external articles that may contact the wearer, such as bed sheetsand undergarments. In preferred embodiments, the back sheet 20 issubstantially impervious to bodily exudates and comprises a laminate ofa non-woven and a thin plastic film such as a thermoplastic film. Theback sheet 20 may comprise breathable materials that permit vapour toescape from the diaper 10 while still preventing bodily exudates frompassing through the back sheet 20. It may be semi-rigid, non-elastic andcan be made fully or partially elasticized and include backing. The backsheets 20 may be assembled in a variety of well-known configurations andare well known in the art.

The diaper 10 comprises a top sheet 18 that is preferably soft,compliant, exhibits good strikethroughs and has a reduced tendency torewet from the liquid absorbent material. The top sheet 18 is placed inclose proximity to the skin of the wearer when the diaper 10 is worn. Inthis way, such top sheet 18 permits bodily exudates to rapidly penetrateit so as to flow toward the absorbent structure 14 more quickly, butpreferably not allowing such bodily exudates to flow back through thetop sheet 18. The top sheet 18 may be constructed from any one of a widerange of liquid and vapour permeable, preferably hydrophilic, materials.The upper and lower surface of the top sheet 18 may be treateddifferently and may for instance include a surfactant on the uppersurface so as to facilitate liquid transfer there through, especially ata central zone or area of the top sheet 18 located over the absorbentstructure 10, and for instance include a hydrophobic agent on the lowersurface to minimize the liquid contained within the absorbent core fromcontact wetting the top sheet 18 thereby reducing rewet values. The topsheet 18 may also be coated with a substance having rash preventing orrash reducing properties (e.g. aloe vera). The top sheet 18 coverssubstantially the entire wearer facing area of the diaper 10, includingsubstantially all of the front waist region 30, back waist region 32,and crotch region 34. Further, the side panels 22 and/or waist featurelayers of the inner region may be formed from the same single top sheetmaterial and, thus, may be referred to as being unitary with the topsheet 18 in forming longitudinal and lateral extensions of the top sheet18 material. Alternatively, the top sheet 18 may be formed from multipledifferent materials which vary across the width of the top sheet 18.Such a multiple piece design allows for creation of preferred propertiesand different zones of the top sheet 18. The top sheet 18 be semi-rigid,non-elastic and can be made fully or partially elasticized. The topsheet 18 may be assembled in a variety of well-known configurations andare well known in the art.

The absorbent structure 14 in FIG. 22 generally is disposed between thetop sheet 18 and the back sheet 20. The absorbent structure 14 maycomprise any absorbent material 110 that is generally compressible,conformable, non-irritating to the wearer's skin, and capable ofabsorbing and retaining bodily exudates. The absorbent structure 14 maycomprise a wide variety of liquid absorbent materials 110 commonly usedin absorbent articles such as fluff pulp, which is generally referred toas airlaid. Examples of other suitable absorbent materials includecreped cellulose wadding; melt blown polymers; chemically stiffened,modified or cross-linked cellulosic fibres; tissue, including tissuewraps and tissue laminates; absorbent foams; absorbent sponges;absorbent polymer materials; absorbent gelling materials; or any otherknown absorbent materials or combinations of materials. The absorbentstructure 14 may further comprise minor amounts (typically less than10%) of non-liquid absorbent materials, such as adhesives, binders,plastics, waxes, oils and the like. The absorbent structure 14 accordingto various embodiments of the invention may be configured to extendsubstantially the full length and/or width of the diaper 10. However,alternatively the absorbent structure 14 according to the invention isnot coextensive with the entire diaper 10 and is limited to certainregions of the diaper 10 such as for instance the crotch region 34. Invarious embodiments, the absorbent structure 14 extends to the edges ofthe diaper 10 and the absorbent material 110 is concentrated in thecrotch region 34 or another target zone of the diaper 10. In stillanother embodiment, the particles can be a combination of absorbentmaterial 110, preferably comprising absorbent polymer material, and skincare particles such as ion exchange resins, deodorant, anti-microbialagents, binder particles, or other beneficial particles.

The diaper 10 may also utilize a pair of containment walls or cuffs 24.Each cuff 24 is a longitudinally extending wall structure preferablypositioned on each side of the absorbent structure 14 and spacedlaterally from the longitudinal axis 36. The longitudinal ends of thecuffs 24 may be attached or joined, for example, to the top sheet 18 inthe front and rear waist regions 30 and 32. Preferably, the ends of thecuffs 24 are tacked down inwardly and attached, for example, by adhesiveor sonic bonding to the lower structure. Such a construction effectivelybiases the cuffs 24 inwardly and is generally considered to cause thecuffs 24 to exhibit improved leakage prevention properties. Preferably,the cuffs 24 are equipped with elastic members 28, which extend along asubstantial length of the cuffs 24. In a common application, the elasticmembers 28 are placed within the cuffs 24, preferably at the top of thecuff 24 while in a stretched condition and then glued or sonic bonded tothe cuff 24 at least at their ends. When released or otherwise allowedrelaxing, the elastic members 28 retract inwardly. When the diaper 10 isworn, the elastic members 28 function to contract the cuffs 24 about thebuttocks and the thighs of the wearer in a manner, which forms a sealsbetween the diaper 10, the buttocks and the thighs. The cuffs 24 may beassembled in a variety of well-known configurations and are well knownin the art.

The diaper 10 may also employ additional layers known in the artincluding an acquisition layer or surge layer, preferably situatedbetween the top sheet and the absorbent core and highloft and/orcoverstock layers. This serves to slow down the flow so that the liquidhas adequate time to be absorbed by the absorbent core.

In order to keep the diaper 10 in place about the wearer, preferably atleast a portion of the back waist region 32 is attached by fastening orsecuring members 46 to at least a portion of the front waist region 30,preferably to form leg openings and an absorbent article waist.Fastening or securing members 46 carry the tensile load around theabsorbent article waist and compliment the elastic members 28 byproviding a quasi-seal between the wearer, the elastic waist feature 26and cuffs 24, so that bodily exudates are contained within the diaper 10which are then absorbed. In other words, so that it does not leakthrough gaps between the wearer and the edge of the diaper 10. Thefastening or securing members 46 may for instance be adhesive,mechanical fasteners, hook and loop features, conceivable strings and/orcombinations thereof, i.e., anything that will secure one end of thediaper 10 to the longitudinally opposite end of the diaper 10. Thefastening or securing members 46 may also be co-adhesive such that theyadhere to each other but not other materials. The fastening or securingmembers 46 and any component thereof may include any material suitablefor such a use, including but not limited to plastics, films, foams,non-woven webs, woven webs, paper, laminates, fibre reinforced plasticsand the like, or combinations thereof. It may be preferable that thematerials making up the fastening or securing members 46 are flexible,extensible and/or elastic, allowing them to better conform to the shapeand movements of the body and thus, reduces the likelihood that thefastening system will irritate or injure the wearer's skin. Preferably,the diaper 10 is affixed to the wearer by tape fasteners which arepermanently affixed to the back sheet 20. Tape fasteners are contactedwith the transversely opposite side panel or ears 22 attached or joinedand extending from the back sheet 20, where they remain affixed due tothe binding compound applied to the fasteners. Alternatively, theabsorbent article may be pants and the like. In this configuration, theabsorbent article may or may not have tape fasteners. Specificdisposability tapes may however also be provided on such absorbentarticles. All fastening and securing elements 46 may be assembled in avariety of well-known configurations and are well known in the art.

The waist regions 30 and 32 each comprise a central region and a pair ofside panels or ears 22 which typically comprise the outer lateralportions of the waist regions. These side panels 22 may be unitary withthe chassis 12 and/or back sheet 20 or may be attached or joined theretoby any means know in the art. In a preferred embodiment of the presentinvention, the side panels 22 positioned in the back waist region 32 areflexible, extensible and/or elastic in at least the lateral direction(i.e., elasticized side panels), in another embodiment the side panels22 are non-elastic, semi-rigid, rigid and/or stiff. This variety of sidepanels 22 are well known.

Furthermore waistbands 26 employing elastic members can be positionedalong the transverse portion of the diaper 10 so that when worn, thewaistbands 26 are positioned along the waist of the wearer. Generally,the waistband 26 preferably creates a seal against the waist so thatbodily exudates do not leak from the regions between the elasticwaistband 26 and the waist of the wearer. Although the bodily exudatesare primarily absorbed by the absorbent materials within the diaper 10,the seal is important considering the assault of liquid by the wearermay overwhelm the absorption rate capacity of the absorbent structure14. Hence, the waistbands 26 contain the liquid while it is beingabsorbed, they are well known in the art. The absorbent article such asa diaper 10 may also include such other features, components andelements as are known in the art including front and rear ear panels,waist cap features, elastics and the like to provide better fit,containment and aesthetic characteristics. These features may beassembled in a variety of well-known configurations and are well knownin the art.

1.-13. (canceled)
 14. A method for depositing particulate material in adesired pattern onto a moving carrier layer; wherein the methodcomprises the steps of providing an endless rotating drum incorporatinga clustering means with perforations corresponding to a desired pattern;driving the clustering means in the same direction as and in closeproximity to the moving carrier layer; feeding a particle materialstream from a particulate material supply means to the clustering means;said particulate material stream comprising absorbent polymer material;directing the particle material stream through the clustering means ontocarrier deposit zones of the carrier layer; placing an auxiliary layeron top of carrier layer on which particulate materials have beendeposited so as to form a sandwich structure.
 15. The method of claim14, wherein the method comprises immobilising, joining and/orrestraining the particulate material to at least one of the carrierlayer and auxiliary layer.
 16. The method of claim 14, wherein at leastone of the carrier layer and the auxiliary layer is made of ahydrophilic non-woven.
 17. The method of claim 14, wherein at least oneof the carrier layer and the auxiliary layer is made of a spunbonded,melt-blown, spunbonded (SMS) layer; or of a spunbonded, melt-blown,melt-blown, spunbonded (SMMS) structure.
 18. The method of claim 14,wherein at least one of the carrier layer and the auxiliary layer ismade of any one of the following materials: a nonwoven containingcellulosic fibers; a paper or tissue sheet; an airlaid, drylaid orwetlaid material.
 19. The method of claim 14, wherein the step ofdirecting the particle material stream through the clustering means usesan air-conveying system.
 20. The method of claim 14, wherein the step ofdirecting the particle material stream through the clustering means usesa vacuum suction system provided in function of the deposit zones of thecarrier layer, creating air flows towards the perforations and thedeposit zones.
 21. The method of claim 14, wherein the absorbent polymermaterial having a mean particle size from about 10 μm to 1000 μm,preferably with less than about 5% by weight having a particle size of 5μm, and preferably with less than about 5% by weight having a particlesize of more than about 1200 μm, said absorbent polymer material beingselected to swell upon contact with liquids, such as bodily exudates.22. The method of claim 14, wherein the desired pattern of theperforations extends along a circumferential- and width-wise directionof the endless rotating drum; and wherein the perforations perforate theendless rotating drum in a radial direction thereof, from an innersurface to an outer surface of the endless rotating drum.
 23. The methodof claim 22, wherein each perforation is formed with a converging funnelstructure in an inlet region thereof.
 24. The method of claim 14,wherein an adhesive is applied on the carrier layer prior to thedirecting of the particle material stream through the clustering meansonto carrier deposit zones of the carrier layer.
 25. The method of claim14, wherein the auxiliary layer is bound or joined to the carrier layerin one or more inter-deposit zones between the carrier deposit zones,via attachment means in the form of grids, patterns, lines, dots and thelike.
 26. The method of claim 25, wherein the attachment means arerealized using at least one of the following: ultra sonic and/or otherthermal, mechanical or thermo- mechanical bonding techniques.
 27. Themethod of claim 25, wherein the attachment means are constructed toprovide any one of the following: adhesive bonds, thermal bonds, sonicbonds, stapling, stitching; and wherein the attachment means areconfigured to provide operable pockets particulate material clustersbetween the carrier layer and auxiliary layer.
 28. The method of claim25, wherein the attachment means are configured to creatingsubstantially penuanent primary attachments and substantially detachableor temporary secondary attachments, wherein the strength of thesecondary attachment means is less than the separating force imparted bythe swelling of the absorbent polymer material when the absorbentpolymer material is exposed to liquids.
 29. A method for depositingparticulate material in a desired pattern onto a moving carrier layer;wherein the method comprises the steps of providing an endless rotatingdrum incorporating a clustering means with perforations corresponding toa desired pattern; driving the clustering means in the same direction asand in close proximity to the moving carrier layer; feeding a particlematerial stream from a particulate material supply means to theclustering means; said particulate material stream comprising absorbentpolymer material; directing the particle material stream through theclustering means onto carrier deposit zones of the carrier layer;placing an auxiliary layer on top of carrier layer on which particulatematerials have been deposited so as to form a sandwich structure;wherein at least one of the carrier layer and the auxiliary layer ismade of a hydrophilic non-woven; wherein the auxiliary layer is bound orjoined to the carrier layer in one or more inter-deposit zones betweenthe carrier deposit zones, via attachment means in the form of grids,patterns, lines, dots and the like.
 30. The method of claim 29, whereinthe attachment means are constructed to provide any one of thefollowing: adhesive bonds, thermal bonds, sonic bonds, stapling,stitching; and wherein the attachment means are configured to provideoperable pockets particulate material clusters between the carrier layerand auxiliary layer.
 31. The method of claim 29, wherein the attachmentmeans are configured to creating substantially permanent primaryattachments and substantially detachable or temporary secondaryattachments, wherein the strength of the secondary attachment means isless than the separating force imparted by the swelling of the absorbentpolymer material when the absorbent polymer material is exposed toliquids.
 32. A method for depositing particulate material in a desiredpattern onto a moving carrier layer; wherein the method comprises thesteps of providing an endless rotating drum incorporating a clusteringmeans with perforations corresponding to a desired pattern; driving theclustering means in the same direction as and in close proximity to themoving carrier layer; feeding a particle material stream from aparticulate material supply means to the clustering means; saidparticulate material stream comprising absorbent polymer material;directing the particle material stream through the clustering means ontocarrier deposit zones of the carrier layer, using at least one of anair-conveying system and a vacuum suction system; placing an auxiliarylayer on top of carrier layer on which particulate materials have beendeposited so as to form a sandwich structure; wherein the desiredpattern of the perforations extends along a circumferential- andwidth-wise direction of the endless rotating drum; and wherein theperforations perforate the endless rotating drum in a radial directionthereof, from an inner surface to an outer surface of the endlessrotating drum; and wherein each perforation is formed with a convergingfunnel structure in an inlet region thereof.
 33. The method of claim 32,wherein the method comprises immobilising, joining and/or restrainingthe particulate material to at least one of the carrier layer andauxiliary layer.